diff --git a/.eslintrc.js b/.eslintrc.js
index c058c631..d31ecc3a 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -12,6 +12,7 @@ module.exports = {
   rules: {
     "arrow-parens": ["error", "as-needed"],
     "no-sparse-arrays": 0,
+    "no-unused-vars": 0,
     "padding-line-between-statements": [
       "error",
       { blankLine: "always", prev: "*", next: "export" },
diff --git a/.gitignore b/.gitignore
index 8ea881d8..60b08df6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ index.umd.js
 **/*.d.ts
 .coverage
 docs/dist
+!*.interface.d.ts
diff --git a/.npmignore b/.npmignore
index b48a1bc6..843307fb 100644
--- a/.npmignore
+++ b/.npmignore
@@ -21,6 +21,7 @@ document.js
 ignore.js
 indexReadme.js
 jest.config.js
+mappings.js
 normalizeLineEndings.js
 package-lock.json
 regenerate.js
diff --git a/README.md b/README.md
index 3a77485d..efbdf1b6 100644
--- a/README.md
+++ b/README.md
@@ -1113,36 +1113,167 @@ Computes a difference between two objects.
 
 #### base64url
 
-Provides a way to encode strings and bytes from and into Base64URL.
+##### decode
 
-##### Type signature
+Decodes the given Base64URL back into string.
+
+###### Type signature
 
 <!-- prettier-ignore-start -->
 ```typescript
-{
-  decode: (text: string, context?: DecodeContext) => string;
-  decodeBytes: (
-    text: string,
-    context?: {
-      atob: (byteString: string) => string;
-      TextDecoder: new (encoding: string) => {
-        decode: (input?: Uint8Array) => string;
-      };
-    }
-  ) => number[];
-  encode: (
-    text: string,
-    context?: {
-      btoa: (byteString: string) => string;
-      TextEncoder: new () => {
-        encode: (input?: string) => Uint8Array;
-      };
-    }
-  ) => string;
-  encodeBytes: (bytes: number[], context?: EncodeContext) => string;
-  fromByteString: (byteString: string) => number[];
-  toByteString: (bytes: number[]) => string;
-}
+(text: string, context?: DecodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+###### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+decode("PDw_Pz8-Pg"); // ⇒ "<<???>>"
+```
+<!-- prettier-ignore-end -->
+
+##### decodeBytes
+
+Decodes the given Base64URL back into byte array.
+
+###### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: DecodeContext) => number[]
+```
+<!-- prettier-ignore-end -->
+
+###### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+decodeBytes("w4Jnw6vCp20-bBsQfA");
+// ⇒ [0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c]
+```
+<!-- prettier-ignore-end -->
+
+##### encode
+
+Encodes the given string into Base64URL.
+
+###### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: EncodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+###### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+encode("<<???>>"); // ⇒ "PDw_Pz8-Pg"
+```
+<!-- prettier-ignore-end -->
+
+##### encodeBytes
+
+Encodes the given bytes into Base64URL.
+
+###### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(bytes: number[], context?: EncodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+###### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+encodeBytes([0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c]);
+// ⇒ "w4Jnw6vCp20-bBsQfA"
+```
+<!-- prettier-ignore-end -->
+
+##### fromBase64
+
+Converts Base64 string into Base64URL one.
+
+###### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(base64: string) => string
+```
+<!-- prettier-ignore-end -->
+
+###### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+fromBase64("PDw/Pz8+Pg=="); // ⇒ "PDw_Pz8-Pg"
+```
+<!-- prettier-ignore-end -->
+
+##### toBase64
+
+Converts Base64URL string into Base64 one.
+
+###### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(base64Url: string) => string
+```
+<!-- prettier-ignore-end -->
+
+###### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+toBase64("PDw_Pz8-Pg"); // ⇒ "PDw/Pz8+Pg=="
+```
+<!-- prettier-ignore-end -->
+
+#### byteString
+
+##### from
+
+Converts string to byte array.
+
+###### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(byteString: string) => number[]
+```
+<!-- prettier-ignore-end -->
+
+###### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+from("PQR"); // ⇒ [80, 81, 82]
+```
+<!-- prettier-ignore-end -->
+
+##### to
+
+Coverts byte array to string.
+
+###### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(bytes: number[]) => string
+```
+<!-- prettier-ignore-end -->
+
+###### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+to([0x50, 0x51, 0x52]); // ⇒ "PQR"
 ```
 <!-- prettier-ignore-end -->
 
diff --git a/compile.js b/compile.js
index 88cb1f3f..83536e3a 100644
--- a/compile.js
+++ b/compile.js
@@ -7,14 +7,14 @@ import path from "path";
 import os from "os";
 import pQueue from "p-queue";
 
+import ignored from "./ignore.js";
+
 const CONCURRENCY = Math.max(1, os.cpus().length - 1);
 
 const { default: PQueue } = pQueue;
 
 const execAsync = promisify(exec);
 
-import ignored from "./ignore.js";
-
 const [sourceIgnoredFiles, ignoredDirectories] = ignored;
 
 const ignoredFiles = sourceIgnoredFiles.filter(x => x !== "index.ts");
diff --git a/docs/scripts/docs.js b/docs/scripts/docs.js
index 8f2ad7e2..713716f1 100644
--- a/docs/scripts/docs.js
+++ b/docs/scripts/docs.js
@@ -1,6 +1,5 @@
 /* eslint-env browser */
 
-// eslint-disable-next-line no-unused-vars
 function tryInREPL(event, scope) {
   var target = event.target;
   var isReplRun = target.matches(".btn-repl");
@@ -25,7 +24,6 @@ function tryInREPL(event, scope) {
   });
 }
 
-// eslint-disable-next-line no-unused-vars
 function toggleTableOfContents() {
   var className = "toc-active";
 
diff --git a/document.js b/document.js
index 28fce76b..d8e97902 100644
--- a/document.js
+++ b/document.js
@@ -4,6 +4,7 @@ import { promises, existsSync } from "fs";
 import path from "path";
 
 import ignored from "./ignore.js";
+import mappings from "./mappings.js";
 
 const template = ({ name, description, signature, examples, questions }) => {
   let content = `# ${name}
@@ -82,11 +83,7 @@ const {
 
 const [, , cwd = process.cwd()] = process.argv;
 
-const mapping = {
-  function: "_function"
-};
-
-const identifier = name => mapping[name] || name;
+const identifier = name => mappings[name] || name;
 
 // Do not match type definition files *.d.ts but match *.ts:
 // https://stackoverflow.com/a/43493203/1384679
diff --git a/encoding/README.md b/encoding/README.md
index 78bb2f76..170cac8b 100644
--- a/encoding/README.md
+++ b/encoding/README.md
@@ -1,34 +1,165 @@
 # base64url
 
-Provides a way to encode strings and bytes from and into Base64URL.
-
-## Type signature
-
-<!-- prettier-ignore-start -->
-```typescript
-{
-  decode: (text: string, context?: DecodeContext) => string;
-  decodeBytes: (
-    text: string,
-    context?: {
-      atob: (byteString: string) => string;
-      TextDecoder: new (encoding: string) => {
-        decode: (input?: Uint8Array) => string;
-      };
-    }
-  ) => number[];
-  encode: (
-    text: string,
-    context?: {
-      btoa: (byteString: string) => string;
-      TextEncoder: new () => {
-        encode: (input?: string) => Uint8Array;
-      };
-    }
-  ) => string;
-  encodeBytes: (bytes: number[], context?: EncodeContext) => string;
-  fromByteString: (byteString: string) => number[];
-  toByteString: (bytes: number[]) => string;
-}
+## decode
+
+Decodes the given Base64URL back into string.
+
+### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: DecodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+decode("PDw_Pz8-Pg"); // ⇒ "<<???>>"
+```
+<!-- prettier-ignore-end -->
+
+## decodeBytes
+
+Decodes the given Base64URL back into byte array.
+
+### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: DecodeContext) => number[]
+```
+<!-- prettier-ignore-end -->
+
+### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+decodeBytes("w4Jnw6vCp20-bBsQfA");
+// ⇒ [0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c]
+```
+<!-- prettier-ignore-end -->
+
+## encode
+
+Encodes the given string into Base64URL.
+
+### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: EncodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+encode("<<???>>"); // ⇒ "PDw_Pz8-Pg"
+```
+<!-- prettier-ignore-end -->
+
+## encodeBytes
+
+Encodes the given bytes into Base64URL.
+
+### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(bytes: number[], context?: EncodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+encodeBytes([0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c]);
+// ⇒ "w4Jnw6vCp20-bBsQfA"
+```
+<!-- prettier-ignore-end -->
+
+## fromBase64
+
+Converts Base64 string into Base64URL one.
+
+### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(base64: string) => string
+```
+<!-- prettier-ignore-end -->
+
+### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+fromBase64("PDw/Pz8+Pg=="); // ⇒ "PDw_Pz8-Pg"
+```
+<!-- prettier-ignore-end -->
+
+## toBase64
+
+Converts Base64URL string into Base64 one.
+
+### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(base64Url: string) => string
+```
+<!-- prettier-ignore-end -->
+
+### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+toBase64("PDw_Pz8-Pg"); // ⇒ "PDw/Pz8+Pg=="
+```
+<!-- prettier-ignore-end -->
+
+# byteString
+
+## from
+
+Converts string to byte array.
+
+### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(byteString: string) => number[]
+```
+<!-- prettier-ignore-end -->
+
+### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+from("PQR"); // ⇒ [80, 81, 82]
+```
+<!-- prettier-ignore-end -->
+
+## to
+
+Coverts byte array to string.
+
+### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(bytes: number[]) => string
+```
+<!-- prettier-ignore-end -->
+
+### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+to([0x50, 0x51, 0x52]); // ⇒ "PQR"
 ```
 <!-- prettier-ignore-end -->
diff --git a/encoding/base64url.js b/encoding/base64url.js
deleted file mode 100644
index 6c6d1a70..00000000
--- a/encoding/base64url.js
+++ /dev/null
@@ -1,66 +0,0 @@
-/* eslint-env browser, node */
-const toArray = typedArray => [...typedArray];
-
-export const toByteString = bytes =>
-  bytes.map(_ => String.fromCharCode(_)).join("");
-
-export const fromByteString = byteString =>
-  [...byteString].map(_ => _.codePointAt(0) || 0);
-
-const ENCODING = "utf-8";
-
-const btoaImplementation = (
-  text,
-  context = typeof window !== "undefined" ? window : undefined
-) =>
-  context
-    ? context.btoa(
-        toByteString(toArray(new context.TextEncoder().encode(text)))
-      )
-    : Buffer.from(text, ENCODING).toString("base64");
-
-const atobImplementation = (
-  text,
-  context = typeof window !== "undefined" ? window : undefined
-) =>
-  context
-    ? new context.TextDecoder(ENCODING).decode(
-        new Uint8Array(fromByteString(context.atob(text)))
-      )
-    : Buffer.from(text, "base64").toString(ENCODING);
-
-export const encode = (text, context) =>
-  btoaImplementation(text, context)
-    .replace(/=/g, "")
-    .replace(/\+/g, "-")
-    .replace(/\//g, "_");
-
-export const decode = (text, context) =>
-  atobImplementation(text.replace(/-/g, "+").replace(/_/g, "/"), context);
-
-export const toBase64Url = base64 =>
-  base64.replace(/\+/g, "-").replace(/\//g, "_");
-
-export const fromBase64Url = base64 =>
-  base64.replace(/-/g, "+").replace(/_/g, "/");
-
-export const encodeBytes = (bytes, context) => {
-  const sourceText = toByteString(bytes);
-
-  return encode(sourceText, context);
-};
-
-export const decodeBytes = (text, context) => {
-  const decoded = decode(text, context);
-
-  return fromByteString(decoded);
-};
-
-export default {
-  decode,
-  decodeBytes,
-  encode,
-  encodeBytes,
-  fromByteString,
-  toByteString
-};
diff --git a/encoding/base64url.jsdom.test.ts b/encoding/base64url.jsdom.test.ts
index 29ad1ea7..adf0a7eb 100644
--- a/encoding/base64url.jsdom.test.ts
+++ b/encoding/base64url.jsdom.test.ts
@@ -1,9 +1,8 @@
 /* eslint-env jest, node */
-import {
-  decode,
-  encode
-  // @ts-ignore ambiguous import
-} from "./base64url.ts";
+// @ts-ignore ambiguous import
+import encode from "./base64url/encode.ts";
+// @ts-ignore ambiguous import
+import decode from "./base64url/decode.ts";
 
 const unicodeText = "Zombies everywhere 🧟";
 
@@ -78,7 +77,13 @@ describe("base64url", () => {
       let out = "";
 
       for (let i = 0; i < s.length; i += 3) {
-        const groupsOfSix = [undefined, undefined, undefined, undefined];
+        const groupsOfSix: [
+          number | undefined,
+          number | undefined,
+          number | undefined,
+          number | undefined
+        ] = [undefined, undefined, undefined, undefined];
+
         groupsOfSix[0] = s.charCodeAt(i) >> 2;
         groupsOfSix[1] = (s.charCodeAt(i) & 0x03) << 4;
 
@@ -88,15 +93,17 @@ describe("base64url", () => {
         }
 
         if (s.length > i + 2) {
-          groupsOfSix[2] |= s.charCodeAt(i + 2) >> 6;
+          groupsOfSix[2] = (groupsOfSix[2] || 0) | (s.charCodeAt(i + 2) >> 6);
           groupsOfSix[3] = s.charCodeAt(i + 2) & 0x3f;
         }
 
         for (let j = 0; j < groupsOfSix.length; j++) {
-          if (typeof groupsOfSix[j] === "undefined") {
+          const x = groupsOfSix[j];
+
+          if (x === undefined) {
             out += "=";
           } else {
-            out += btoaLookup(groupsOfSix[j]);
+            out += btoaLookup(x);
           }
         }
       }
@@ -120,19 +127,21 @@ describe("base64url", () => {
       throw new RangeError("Index out of range.");
     };
 
+    const globalAny: any = global;
+
     const context = {
       atob,
       btoa,
-      TextEncoder: global["TextEncoder"],
-      TextDecoder: global["TextDecoder"]
+      TextEncoder: globalAny["TextEncoder"],
+      TextDecoder: globalAny["TextDecoder"]
     };
 
     expect(decode(encode(unicodeText, context), context)).toEqual(unicodeText);
 
-    global["window"] = context;
+    globalAny["window"] = context;
 
     expect(decode(encode(unicodeText))).toEqual(unicodeText);
 
-    delete global["window"];
+    delete globalAny["window"];
   });
 });
diff --git a/encoding/base64url.json b/encoding/base64url.json
deleted file mode 100644
index 34c52133..00000000
--- a/encoding/base64url.json
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  "name": "base64url",
-  "description": "Provides a way to encode strings and bytes from and into Base64URL.",
-  "signature": "{\n  decode: (text: string, context?: DecodeContext) => string;\n  decodeBytes: (\n    text: string,\n    context?: {\n      atob: (byteString: string) => string;\n      TextDecoder: new (encoding: string) => {\n        decode: (input?: Uint8Array) => string;\n      };\n    }\n  ) => number[];\n  encode: (\n    text: string,\n    context?: {\n      btoa: (byteString: string) => string;\n      TextEncoder: new () => {\n        encode: (input?: string) => Uint8Array;\n      };\n    }\n  ) => string;\n  encodeBytes: (bytes: number[], context?: EncodeContext) => string;\n  fromByteString: (byteString: string) => number[];\n  toByteString: (bytes: number[]) => string;\n}",
-  "examples": [
-    {
-      "language": "javascript",
-      "content": "base64url(); // ⇒ TODO"
-    }
-  ],
-  "questions": ["TODO: List questions that may this function answers."]
-}
diff --git a/encoding/base64url.md b/encoding/base64url.md
deleted file mode 100644
index 78bb2f76..00000000
--- a/encoding/base64url.md
+++ /dev/null
@@ -1,34 +0,0 @@
-# base64url
-
-Provides a way to encode strings and bytes from and into Base64URL.
-
-## Type signature
-
-<!-- prettier-ignore-start -->
-```typescript
-{
-  decode: (text: string, context?: DecodeContext) => string;
-  decodeBytes: (
-    text: string,
-    context?: {
-      atob: (byteString: string) => string;
-      TextDecoder: new (encoding: string) => {
-        decode: (input?: Uint8Array) => string;
-      };
-    }
-  ) => number[];
-  encode: (
-    text: string,
-    context?: {
-      btoa: (byteString: string) => string;
-      TextEncoder: new () => {
-        encode: (input?: string) => Uint8Array;
-      };
-    }
-  ) => string;
-  encodeBytes: (bytes: number[], context?: EncodeContext) => string;
-  fromByteString: (byteString: string) => number[];
-  toByteString: (bytes: number[]) => string;
-}
-```
-<!-- prettier-ignore-end -->
diff --git a/encoding/base64url.test.ts b/encoding/base64url.test.ts
index f6a3c99c..ebb2b981 100644
--- a/encoding/base64url.test.ts
+++ b/encoding/base64url.test.ts
@@ -1,15 +1,20 @@
 /* eslint-env jest, node */
-import {
-  decode,
-  decodeBytes,
-  encode,
-  encodeBytes,
-  fromBase64Url,
-  fromByteString,
-  toBase64Url,
-  toByteString
-  // @ts-ignore ambiguous import
-} from "./base64url.ts";
+// @ts-ignore ambiguous import
+import encode from "./base64url/encode.ts";
+// @ts-ignore ambiguous import
+import decode from "./base64url/decode.ts";
+// @ts-ignore ambiguous import
+import encodeBytes from "./base64url/encodeBytes.ts";
+// @ts-ignore ambiguous import
+import decodeBytes from "./base64url/decodeBytes.ts";
+// @ts-ignore ambiguous import
+import toBase64 from "./base64url/toBase64.ts";
+// @ts-ignore ambiguous import
+import fromBase64 from "./base64url/fromBase64.ts";
+// @ts-ignore ambiguous import
+import fromByteString from "./byteString/from.ts";
+// @ts-ignore ambiguous import
+import toByteString from "./byteString/to.ts";
 
 // @ts-ignore ambiguous import
 import range from "../array/range.ts";
@@ -62,6 +67,14 @@ describe("base64url", () => {
     expect(encode(text)).toEqual("QmFzZTY0VVJMIGVuY29kZS9kZWNvZGUgdGVzdA");
   });
 
+  it("properly replaces non-URL-safe characters", () => {
+    expect(encode("<<???>>")).toEqual("PDw_Pz8-Pg");
+    expect(Buffer.from("<<???>>", "utf-8").toString("base64")).toEqual(
+      "PDw/Pz8+Pg=="
+    );
+    expect(decode(encode("<<???>>"))).toEqual("<<???>>");
+  });
+
   it("is does not include padding characters", () => {
     const text = "Zażółć gęślą jaźń";
 
@@ -88,6 +101,15 @@ describe("base64url", () => {
     expect(decode(encode(text))).toEqual(text);
   });
 
+  it("encodes/decodes bytes", () => {
+    const bytes = [0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c];
+
+    const encoded = "w4Jnw6vCp20-bBsQfA";
+
+    expect(encodeBytes(bytes)).toEqual(encoded);
+    expect(decodeBytes(encoded)).toEqual(bytes);
+  });
+
   it("handles Unicode", () => {
     expect(decode(encode(unicodeText))).toEqual(unicodeText);
   });
@@ -99,16 +121,42 @@ describe("base64url", () => {
   it("converts base64 to base64URL", () => {
     const text = toByteString(range(256));
 
-    expect(toBase64Url(Buffer.from(text, "utf-8").toString("base64"))).toEqual(
+    expect(fromBase64(Buffer.from(text, "utf-8").toString("base64"))).toEqual(
       encode(text)
     );
   });
 
   it("converts base64URL to base64", () => {
     const text = toByteString(range(256));
+    const base64url = encode(text);
+    const encoded = toBase64(base64url);
+    const expected = Buffer.from(text, "utf-8").toString("base64");
 
-    expect(fromBase64Url(encode(text))).toEqual(
-      Buffer.from(text, "utf-8").toString("base64")
-    );
+    expect(encoded).toEqual(expected);
+  });
+
+  it("fromBase64 strips padding characters", () => {
+    expect(fromBase64("PDw/Pz8+Pg==")).toEqual("PDw_Pz8-Pg");
+  });
+
+  it("toBase64 adds padding characters when needed", () => {
+    expect(toBase64("PDw_Pz8-Pg")).toEqual("PDw/Pz8+Pg==");
+  });
+
+  it("converts base64 to base64URL and vice versa", () => {
+    const base64 = "PDw/Pz8+Pg==";
+    const base64url = "PDw_Pz8-Pg";
+
+    expect(fromBase64(base64)).toEqual(base64url);
+    expect(toBase64(base64url)).toEqual(base64);
+  });
+
+  it("encodes/decodes bytes to and from string", () => {
+    const bytes = [0x50, 0x51, 0x52];
+
+    const encoded = "PQR";
+
+    expect(toByteString(bytes)).toEqual(encoded);
+    expect(fromByteString(encoded)).toEqual(bytes);
   });
 });
diff --git a/encoding/base64url.ts b/encoding/base64url.ts
deleted file mode 100644
index 98c75bc4..00000000
--- a/encoding/base64url.ts
+++ /dev/null
@@ -1,99 +0,0 @@
-/* eslint-env browser, node */
-
-export interface EncodeContext {
-  btoa: (byteString: string) => string;
-  TextEncoder: new () => {
-    encode: { (input?: string): Uint8Array };
-  };
-}
-
-export interface DecodeContext {
-  atob: (byteString: string) => string;
-  TextDecoder: new (encoding: string) => {
-    decode: (input?: Uint8Array) => string;
-  };
-}
-
-const toArray = (typedArray: Uint8Array): number[] => [...typedArray];
-
-export const toByteString = (bytes: number[]) =>
-  bytes.map(_ => String.fromCharCode(_)).join("");
-
-export const fromByteString = (byteString: string): number[] =>
-  [...byteString].map(_ => _.codePointAt(0) || 0);
-
-const ENCODING = "utf-8";
-
-const btoaImplementation = (
-  text: string,
-  context: EncodeContext | undefined = typeof window !== "undefined"
-    ? window
-    : undefined
-) =>
-  context
-    ? context.btoa(
-        toByteString(toArray(new context.TextEncoder().encode(text)))
-      )
-    : Buffer.from(text, ENCODING).toString("base64");
-
-const atobImplementation = (
-  text: string,
-  context: DecodeContext | undefined = typeof window !== "undefined"
-    ? window
-    : undefined
-) =>
-  context
-    ? new context.TextDecoder(ENCODING).decode(
-        new Uint8Array(fromByteString(context.atob(text)))
-      )
-    : Buffer.from(text, "base64").toString(ENCODING);
-
-export const encode = (
-  text: string,
-  context?: {
-    btoa: (byteString: string) => string;
-    TextEncoder: new () => { encode: (input?: string) => Uint8Array };
-  }
-) =>
-  btoaImplementation(text, context)
-    .replace(/=/g, "")
-    .replace(/\+/g, "-")
-    .replace(/\//g, "_");
-
-export const decode = (text: string, context?: DecodeContext) =>
-  atobImplementation(text.replace(/-/g, "+").replace(/_/g, "/"), context);
-
-export const toBase64Url = (base64: string) =>
-  base64.replace(/\+/g, "-").replace(/\//g, "_");
-
-export const fromBase64Url = (base64: string) =>
-  base64.replace(/-/g, "+").replace(/_/g, "/");
-
-export const encodeBytes = (bytes: number[], context?: EncodeContext) => {
-  const sourceText = toByteString(bytes);
-
-  return encode(sourceText, context);
-};
-
-export const decodeBytes = (
-  text: string,
-  context?: {
-    atob: (byteString: string) => string;
-    TextDecoder: new (encoding: string) => {
-      decode: (input?: Uint8Array) => string;
-    };
-  }
-) => {
-  const decoded = decode(text, context);
-
-  return fromByteString(decoded);
-};
-
-export default {
-  decode,
-  decodeBytes,
-  encode,
-  encodeBytes,
-  fromByteString,
-  toByteString
-};
diff --git a/encoding/base64url/DecodeContext.interface.d.ts b/encoding/base64url/DecodeContext.interface.d.ts
new file mode 100644
index 00000000..a477cedd
--- /dev/null
+++ b/encoding/base64url/DecodeContext.interface.d.ts
@@ -0,0 +1,6 @@
+export interface DecodeContext {
+  atob: (byteString: string) => string;
+  TextDecoder: new (encoding: string) => {
+    decode: (input?: Uint8Array) => string;
+  };
+}
diff --git a/encoding/base64url/EncodeContext.interface.d.ts b/encoding/base64url/EncodeContext.interface.d.ts
new file mode 100644
index 00000000..fa791926
--- /dev/null
+++ b/encoding/base64url/EncodeContext.interface.d.ts
@@ -0,0 +1,6 @@
+export interface EncodeContext {
+  btoa: (byteString: string) => string;
+  TextEncoder: new () => {
+    encode: { (input?: string): Uint8Array };
+  };
+}
diff --git a/encoding/base64url/README.md b/encoding/base64url/README.md
new file mode 100644
index 00000000..e02753f8
--- /dev/null
+++ b/encoding/base64url/README.md
@@ -0,0 +1,121 @@
+# decode
+
+Decodes the given Base64URL back into string.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: DecodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+decode("PDw_Pz8-Pg"); // ⇒ "<<???>>"
+```
+<!-- prettier-ignore-end -->
+
+# decodeBytes
+
+Decodes the given Base64URL back into byte array.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: DecodeContext) => number[]
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+decodeBytes("w4Jnw6vCp20-bBsQfA");
+// ⇒ [0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c]
+```
+<!-- prettier-ignore-end -->
+
+# encode
+
+Encodes the given string into Base64URL.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: EncodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+encode("<<???>>"); // ⇒ "PDw_Pz8-Pg"
+```
+<!-- prettier-ignore-end -->
+
+# encodeBytes
+
+Encodes the given bytes into Base64URL.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(bytes: number[], context?: EncodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+encodeBytes([0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c]);
+// ⇒ "w4Jnw6vCp20-bBsQfA"
+```
+<!-- prettier-ignore-end -->
+
+# fromBase64
+
+Converts Base64 string into Base64URL one.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(base64: string) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+fromBase64("PDw/Pz8+Pg=="); // ⇒ "PDw_Pz8-Pg"
+```
+<!-- prettier-ignore-end -->
+
+# toBase64
+
+Converts Base64URL string into Base64 one.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(base64Url: string) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+toBase64("PDw_Pz8-Pg"); // ⇒ "PDw/Pz8+Pg=="
+```
+<!-- prettier-ignore-end -->
diff --git a/encoding/base64url/decode.js b/encoding/base64url/decode.js
new file mode 100644
index 00000000..4c4f663a
--- /dev/null
+++ b/encoding/base64url/decode.js
@@ -0,0 +1,17 @@
+/* eslint-env browser, node */
+import fromByteString from "../byteString/from.js";
+
+const ENCODING = "utf-8";
+
+const atobImplementation = (
+  text,
+  context = typeof window !== "undefined" ? window : undefined
+) =>
+  context
+    ? new context.TextDecoder(ENCODING).decode(
+        new Uint8Array(fromByteString(context.atob(text)))
+      )
+    : Buffer.from(text, "base64").toString(ENCODING);
+
+export default (text, context) =>
+  atobImplementation(text.replace(/-/g, "+").replace(/_/g, "/"), context);
diff --git a/encoding/base64url/decode.json b/encoding/base64url/decode.json
new file mode 100644
index 00000000..53086a6c
--- /dev/null
+++ b/encoding/base64url/decode.json
@@ -0,0 +1,12 @@
+{
+  "name": "decode",
+  "description": "Decodes the given Base64URL back into string.",
+  "signature": "(text: string, context?: DecodeContext) => string",
+  "examples": [
+    {
+      "language": "javascript",
+      "content": "decode(\"PDw_Pz8-Pg\"); // ⇒ \"<<???>>\""
+    }
+  ],
+  "questions": ["TODO: List questions that may this function answers."]
+}
diff --git a/encoding/base64url/decode.md b/encoding/base64url/decode.md
new file mode 100644
index 00000000..a75a8ad2
--- /dev/null
+++ b/encoding/base64url/decode.md
@@ -0,0 +1,19 @@
+# decode
+
+Decodes the given Base64URL back into string.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: DecodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+decode("PDw_Pz8-Pg"); // ⇒ "<<???>>"
+```
+<!-- prettier-ignore-end -->
diff --git a/encoding/base64url/decode.ts b/encoding/base64url/decode.ts
new file mode 100644
index 00000000..a6de6290
--- /dev/null
+++ b/encoding/base64url/decode.ts
@@ -0,0 +1,20 @@
+/* eslint-env browser, node */
+import fromByteString from "../byteString/from";
+import { DecodeContext } from "./DecodeContext.interface";
+
+const ENCODING = "utf-8";
+
+const atobImplementation = (
+  text: string,
+  context: DecodeContext | undefined = typeof window !== "undefined"
+    ? window
+    : undefined
+) =>
+  context
+    ? new context.TextDecoder(ENCODING).decode(
+        new Uint8Array(fromByteString(context.atob(text)))
+      )
+    : Buffer.from(text, "base64").toString(ENCODING);
+
+export default (text: string, context?: DecodeContext) =>
+  atobImplementation(text.replace(/-/g, "+").replace(/_/g, "/"), context);
diff --git a/encoding/base64url/decodeBytes.js b/encoding/base64url/decodeBytes.js
new file mode 100644
index 00000000..7328e957
--- /dev/null
+++ b/encoding/base64url/decodeBytes.js
@@ -0,0 +1,9 @@
+/* eslint-env browser, node */
+import decode from "./decode.js";
+import fromByteString from "../byteString/from.js";
+
+export default (text, context) => {
+  const decoded = decode(text, context);
+
+  return fromByteString(decoded);
+};
diff --git a/encoding/base64url/decodeBytes.json b/encoding/base64url/decodeBytes.json
new file mode 100644
index 00000000..9630f2f7
--- /dev/null
+++ b/encoding/base64url/decodeBytes.json
@@ -0,0 +1,12 @@
+{
+  "name": "decodeBytes",
+  "description": "Decodes the given Base64URL back into byte array.",
+  "signature": "(text: string, context?: DecodeContext) => number[]",
+  "examples": [
+    {
+      "language": "javascript",
+      "content": "decodeBytes(\"w4Jnw6vCp20-bBsQfA\");\n// ⇒ [0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c]"
+    }
+  ],
+  "questions": ["TODO: List questions that may this function answers."]
+}
diff --git a/encoding/base64url/decodeBytes.md b/encoding/base64url/decodeBytes.md
new file mode 100644
index 00000000..37a827af
--- /dev/null
+++ b/encoding/base64url/decodeBytes.md
@@ -0,0 +1,20 @@
+# decodeBytes
+
+Decodes the given Base64URL back into byte array.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: DecodeContext) => number[]
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+decodeBytes("w4Jnw6vCp20-bBsQfA");
+// ⇒ [0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c]
+```
+<!-- prettier-ignore-end -->
diff --git a/encoding/base64url/decodeBytes.ts b/encoding/base64url/decodeBytes.ts
new file mode 100644
index 00000000..249ab5ae
--- /dev/null
+++ b/encoding/base64url/decodeBytes.ts
@@ -0,0 +1,10 @@
+/* eslint-env browser, node */
+import decode from "./decode";
+import fromByteString from "../byteString/from";
+import { DecodeContext } from "./DecodeContext.interface";
+
+export default (text: string, context?: DecodeContext) => {
+  const decoded = decode(text, context);
+
+  return fromByteString(decoded);
+};
diff --git a/encoding/base64url/encode.js b/encoding/base64url/encode.js
new file mode 100644
index 00000000..7876e8a8
--- /dev/null
+++ b/encoding/base64url/encode.js
@@ -0,0 +1,21 @@
+/* eslint-env browser, node */
+import toByteString from "../byteString/to.js";
+
+const toArray = typedArray => [...typedArray];
+const ENCODING = "utf-8";
+
+const btoaImplementation = (
+  text,
+  context = typeof window !== "undefined" ? window : undefined
+) =>
+  context
+    ? context.btoa(
+        toByteString(toArray(new context.TextEncoder().encode(text)))
+      )
+    : Buffer.from(text, ENCODING).toString("base64");
+
+export default (text, context) =>
+  btoaImplementation(text, context)
+    .replace(/=/g, "")
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_");
diff --git a/encoding/base64url/encode.json b/encoding/base64url/encode.json
new file mode 100644
index 00000000..e63c07d4
--- /dev/null
+++ b/encoding/base64url/encode.json
@@ -0,0 +1,12 @@
+{
+  "name": "encode",
+  "description": "Encodes the given string into Base64URL.",
+  "signature": "(text: string, context?: EncodeContext) => string",
+  "examples": [
+    {
+      "language": "javascript",
+      "content": "encode(\"<<???>>\"); // ⇒ \"PDw_Pz8-Pg\""
+    }
+  ],
+  "questions": ["TODO: List questions that may this function answers."]
+}
diff --git a/encoding/base64url/encode.md b/encoding/base64url/encode.md
new file mode 100644
index 00000000..7d24bf7d
--- /dev/null
+++ b/encoding/base64url/encode.md
@@ -0,0 +1,19 @@
+# encode
+
+Encodes the given string into Base64URL.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(text: string, context?: EncodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+encode("<<???>>"); // ⇒ "PDw_Pz8-Pg"
+```
+<!-- prettier-ignore-end -->
diff --git a/encoding/base64url/encode.ts b/encoding/base64url/encode.ts
new file mode 100644
index 00000000..d32c8285
--- /dev/null
+++ b/encoding/base64url/encode.ts
@@ -0,0 +1,25 @@
+/* eslint-env browser, node */
+import toByteString from "../byteString/to";
+import { EncodeContext } from "./EncodeContext.interface";
+
+const toArray = (typedArray: Uint8Array): number[] => [...typedArray];
+
+const ENCODING = "utf-8";
+
+const btoaImplementation = (
+  text: string,
+  context: EncodeContext | undefined = typeof window !== "undefined"
+    ? window
+    : undefined
+) =>
+  context
+    ? context.btoa(
+        toByteString(toArray(new context.TextEncoder().encode(text)))
+      )
+    : Buffer.from(text, ENCODING).toString("base64");
+
+export default (text: string, context?: EncodeContext) =>
+  btoaImplementation(text, context)
+    .replace(/=/g, "")
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_");
diff --git a/encoding/base64url/encodeBytes.js b/encoding/base64url/encodeBytes.js
new file mode 100644
index 00000000..e4935e7b
--- /dev/null
+++ b/encoding/base64url/encodeBytes.js
@@ -0,0 +1,9 @@
+/* eslint-env browser, node */
+import encode from "./encode.js";
+import toByteString from "../byteString/to.js";
+
+export default (bytes, context) => {
+  const sourceText = toByteString(bytes);
+
+  return encode(sourceText, context);
+};
diff --git a/encoding/base64url/encodeBytes.json b/encoding/base64url/encodeBytes.json
new file mode 100644
index 00000000..1f00edd7
--- /dev/null
+++ b/encoding/base64url/encodeBytes.json
@@ -0,0 +1,12 @@
+{
+  "name": "encodeBytes",
+  "description": "Encodes the given bytes into Base64URL.",
+  "signature": "(bytes: number[], context?: EncodeContext) => string",
+  "examples": [
+    {
+      "language": "javascript",
+      "content": "encodeBytes([0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c]);\n// ⇒ \"w4Jnw6vCp20-bBsQfA\""
+    }
+  ],
+  "questions": ["TODO: List questions that may this function answers."]
+}
diff --git a/encoding/base64url/encodeBytes.md b/encoding/base64url/encodeBytes.md
new file mode 100644
index 00000000..2015a68c
--- /dev/null
+++ b/encoding/base64url/encodeBytes.md
@@ -0,0 +1,20 @@
+# encodeBytes
+
+Encodes the given bytes into Base64URL.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(bytes: number[], context?: EncodeContext) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+encodeBytes([0xc2, 0x67, 0xeb, 0xa7, 0x6d, 0x3e, 0x6c, 0x1b, 0x10, 0x7c]);
+// ⇒ "w4Jnw6vCp20-bBsQfA"
+```
+<!-- prettier-ignore-end -->
diff --git a/encoding/base64url/encodeBytes.ts b/encoding/base64url/encodeBytes.ts
new file mode 100644
index 00000000..833e1e8c
--- /dev/null
+++ b/encoding/base64url/encodeBytes.ts
@@ -0,0 +1,10 @@
+/* eslint-env browser, node */
+import encode from "./encode";
+import toByteString from "../byteString/to";
+import { EncodeContext } from "./EncodeContext.interface";
+
+export default (bytes: number[], context?: EncodeContext) => {
+  const sourceText = toByteString(bytes);
+
+  return encode(sourceText, context);
+};
diff --git a/encoding/base64url/fromBase64.js b/encoding/base64url/fromBase64.js
new file mode 100644
index 00000000..a03f49f6
--- /dev/null
+++ b/encoding/base64url/fromBase64.js
@@ -0,0 +1,5 @@
+export default base64 =>
+  base64
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=/g, "");
diff --git a/encoding/base64url/fromBase64.json b/encoding/base64url/fromBase64.json
new file mode 100644
index 00000000..fdd321e1
--- /dev/null
+++ b/encoding/base64url/fromBase64.json
@@ -0,0 +1,12 @@
+{
+  "name": "fromBase64",
+  "description": "Converts Base64 string into Base64URL one.",
+  "signature": "(base64: string) => string",
+  "examples": [
+    {
+      "language": "javascript",
+      "content": "fromBase64(\"PDw/Pz8+Pg==\"); // ⇒ \"PDw_Pz8-Pg\""
+    }
+  ],
+  "questions": ["TODO: List questions that may this function answers."]
+}
diff --git a/encoding/base64url/fromBase64.md b/encoding/base64url/fromBase64.md
new file mode 100644
index 00000000..fa877d00
--- /dev/null
+++ b/encoding/base64url/fromBase64.md
@@ -0,0 +1,19 @@
+# fromBase64
+
+Converts Base64 string into Base64URL one.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(base64: string) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+fromBase64("PDw/Pz8+Pg=="); // ⇒ "PDw_Pz8-Pg"
+```
+<!-- prettier-ignore-end -->
diff --git a/encoding/base64url/fromBase64.ts b/encoding/base64url/fromBase64.ts
new file mode 100644
index 00000000..f5b9f97c
--- /dev/null
+++ b/encoding/base64url/fromBase64.ts
@@ -0,0 +1,5 @@
+export default (base64: string) =>
+  base64
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=/g, "");
diff --git a/encoding/base64url/index.js b/encoding/base64url/index.js
new file mode 100644
index 00000000..5b34a5d6
--- /dev/null
+++ b/encoding/base64url/index.js
@@ -0,0 +1,17 @@
+import decode from "./decode.js";
+import decodeBytes from "./decodeBytes.js";
+import encode from "./encode.js";
+import encodeBytes from "./encodeBytes.js";
+import fromBase64 from "./fromBase64.js";
+import toBase64 from "./toBase64.js";
+
+export { decode, decodeBytes, encode, encodeBytes, fromBase64, toBase64 };
+
+export default {
+  decode,
+  decodeBytes,
+  encode,
+  encodeBytes,
+  fromBase64,
+  toBase64
+};
diff --git a/encoding/base64url/index.ts b/encoding/base64url/index.ts
new file mode 100644
index 00000000..51e49552
--- /dev/null
+++ b/encoding/base64url/index.ts
@@ -0,0 +1,17 @@
+import decode from "./decode";
+import decodeBytes from "./decodeBytes";
+import encode from "./encode";
+import encodeBytes from "./encodeBytes";
+import fromBase64 from "./fromBase64";
+import toBase64 from "./toBase64";
+
+export { decode, decodeBytes, encode, encodeBytes, fromBase64, toBase64 };
+
+export default {
+  decode,
+  decodeBytes,
+  encode,
+  encodeBytes,
+  fromBase64,
+  toBase64
+};
diff --git a/encoding/base64url/toBase64.js b/encoding/base64url/toBase64.js
new file mode 100644
index 00000000..ef94bd62
--- /dev/null
+++ b/encoding/base64url/toBase64.js
@@ -0,0 +1,5 @@
+export default base64Url =>
+  base64Url
+    .replace(/-/g, "+")
+    .replace(/_/g, "/")
+    .padEnd(Math.ceil(base64Url.length / 4) * 4, "=");
diff --git a/encoding/base64url/toBase64.json b/encoding/base64url/toBase64.json
new file mode 100644
index 00000000..2b7631e6
--- /dev/null
+++ b/encoding/base64url/toBase64.json
@@ -0,0 +1,12 @@
+{
+  "name": "toBase64",
+  "description": "Converts Base64URL string into Base64 one.",
+  "signature": "(base64Url: string) => string",
+  "examples": [
+    {
+      "language": "javascript",
+      "content": "toBase64(\"PDw_Pz8-Pg\"); // ⇒ \"PDw/Pz8+Pg==\""
+    }
+  ],
+  "questions": ["TODO: List questions that may this function answers."]
+}
diff --git a/encoding/base64url/toBase64.md b/encoding/base64url/toBase64.md
new file mode 100644
index 00000000..5856bf2d
--- /dev/null
+++ b/encoding/base64url/toBase64.md
@@ -0,0 +1,19 @@
+# toBase64
+
+Converts Base64URL string into Base64 one.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(base64Url: string) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+toBase64("PDw_Pz8-Pg"); // ⇒ "PDw/Pz8+Pg=="
+```
+<!-- prettier-ignore-end -->
diff --git a/encoding/base64url/toBase64.ts b/encoding/base64url/toBase64.ts
new file mode 100644
index 00000000..146ef611
--- /dev/null
+++ b/encoding/base64url/toBase64.ts
@@ -0,0 +1,5 @@
+export default (base64Url: string) =>
+  base64Url
+    .replace(/-/g, "+")
+    .replace(/_/g, "/")
+    .padEnd(Math.ceil(base64Url.length / 4) * 4, "=");
diff --git a/encoding/byteString/README.md b/encoding/byteString/README.md
new file mode 100644
index 00000000..78f90898
--- /dev/null
+++ b/encoding/byteString/README.md
@@ -0,0 +1,39 @@
+# from
+
+Converts string to byte array.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(byteString: string) => number[]
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+from("PQR"); // ⇒ [80, 81, 82]
+```
+<!-- prettier-ignore-end -->
+
+# to
+
+Coverts byte array to string.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(bytes: number[]) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+to([0x50, 0x51, 0x52]); // ⇒ "PQR"
+```
+<!-- prettier-ignore-end -->
diff --git a/encoding/byteString/from.js b/encoding/byteString/from.js
new file mode 100644
index 00000000..dac94828
--- /dev/null
+++ b/encoding/byteString/from.js
@@ -0,0 +1 @@
+export default byteString => [...byteString].map(_ => _.codePointAt(0) || 0);
diff --git a/encoding/byteString/from.json b/encoding/byteString/from.json
new file mode 100644
index 00000000..fee05323
--- /dev/null
+++ b/encoding/byteString/from.json
@@ -0,0 +1,12 @@
+{
+  "name": "from",
+  "description": "Converts string to byte array.",
+  "signature": "(byteString: string) => number[]",
+  "examples": [
+    {
+      "language": "javascript",
+      "content": "from(\"PQR\"); // ⇒ [80, 81, 82]"
+    }
+  ],
+  "questions": ["TODO: List questions that may this function answers."]
+}
diff --git a/encoding/byteString/from.md b/encoding/byteString/from.md
new file mode 100644
index 00000000..64050ff5
--- /dev/null
+++ b/encoding/byteString/from.md
@@ -0,0 +1,19 @@
+# from
+
+Converts string to byte array.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(byteString: string) => number[]
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+from("PQR"); // ⇒ [80, 81, 82]
+```
+<!-- prettier-ignore-end -->
diff --git a/encoding/byteString/from.ts b/encoding/byteString/from.ts
new file mode 100644
index 00000000..c0ebd1b3
--- /dev/null
+++ b/encoding/byteString/from.ts
@@ -0,0 +1,2 @@
+export default (byteString: string): number[] =>
+  [...byteString].map(_ => _.codePointAt(0) || 0);
diff --git a/encoding/byteString/index.js b/encoding/byteString/index.js
new file mode 100644
index 00000000..fa795a66
--- /dev/null
+++ b/encoding/byteString/index.js
@@ -0,0 +1,6 @@
+import from from "./from.js";
+import to from "./to.js";
+
+export { from, to };
+
+export default { from, to };
diff --git a/encoding/byteString/index.ts b/encoding/byteString/index.ts
new file mode 100644
index 00000000..f1f3d34f
--- /dev/null
+++ b/encoding/byteString/index.ts
@@ -0,0 +1,6 @@
+import from from "./from";
+import to from "./to";
+
+export { from, to };
+
+export default { from, to };
diff --git a/encoding/byteString/to.js b/encoding/byteString/to.js
new file mode 100644
index 00000000..b4a4302d
--- /dev/null
+++ b/encoding/byteString/to.js
@@ -0,0 +1 @@
+export default bytes => bytes.map(_ => String.fromCharCode(_)).join("");
diff --git a/encoding/byteString/to.json b/encoding/byteString/to.json
new file mode 100644
index 00000000..c63fe0c8
--- /dev/null
+++ b/encoding/byteString/to.json
@@ -0,0 +1,12 @@
+{
+  "name": "to",
+  "description": "Coverts byte array to string.",
+  "signature": "(bytes: number[]) => string",
+  "examples": [
+    {
+      "language": "javascript",
+      "content": "to([0x50, 0x51, 0x52]); // ⇒ \"PQR\""
+    }
+  ],
+  "questions": ["TODO: List questions that may this function answers."]
+}
diff --git a/encoding/byteString/to.md b/encoding/byteString/to.md
new file mode 100644
index 00000000..ff0c0a8c
--- /dev/null
+++ b/encoding/byteString/to.md
@@ -0,0 +1,19 @@
+# to
+
+Coverts byte array to string.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(bytes: number[]) => string
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+to([0x50, 0x51, 0x52]); // ⇒ "PQR"
+```
+<!-- prettier-ignore-end -->
diff --git a/encoding/byteString/to.ts b/encoding/byteString/to.ts
new file mode 100644
index 00000000..7066f842
--- /dev/null
+++ b/encoding/byteString/to.ts
@@ -0,0 +1,2 @@
+export default (bytes: number[]) =>
+  bytes.map(_ => String.fromCharCode(_)).join("");
diff --git a/encoding/index.js b/encoding/index.js
index 78553ab2..48b2fa76 100644
--- a/encoding/index.js
+++ b/encoding/index.js
@@ -1,5 +1,6 @@
-import base64url from "./base64url.js";
+import base64url from "./base64url/index.js";
+import byteString from "./byteString/index.js";
 
-export { base64url };
+export { base64url, byteString };
 
-export default { base64url };
+export default { base64url, byteString };
diff --git a/encoding/index.ts b/encoding/index.ts
index 347392d6..6de7c628 100644
--- a/encoding/index.ts
+++ b/encoding/index.ts
@@ -1,5 +1,6 @@
-import base64url from "./base64url";
+import base64url from "./base64url/index";
+import byteString from "./byteString/index";
 
-export { base64url };
+export { base64url, byteString };
 
-export default { base64url };
+export default { base64url, byteString };
diff --git a/ignore.js b/ignore.js
index a45af36b..7a1e106f 100644
--- a/ignore.js
+++ b/ignore.js
@@ -21,6 +21,7 @@ const ignoredFiles = [
   "indexReadme.js",
   "jest.config.js",
   "LICENSE",
+  "mappings.js",
   "normalizeLineEndings.js",
   "package-lock.json",
   "package.json",
diff --git a/indexReadme.js b/indexReadme.js
index 546bf64b..1a6feb2f 100644
--- a/indexReadme.js
+++ b/indexReadme.js
@@ -4,6 +4,7 @@ import { promises, existsSync } from "fs";
 import path from "path";
 
 import ignored from "./ignore.js";
+import mappings from "./mappings.js";
 
 const [ignoredFiles, ignoredDirectories] = ignored;
 
@@ -15,11 +16,7 @@ const {
 
 const [, , cwd = process.cwd()] = process.argv;
 
-const mapping = {
-  function: "_function"
-};
-
-const identifier = name => mapping[name] || name;
+const identifier = name => mappings[name] || name;
 
 // Do not match type definition files *.d.ts but match *.ts:
 // https://stackoverflow.com/a/43493203/1384679
diff --git a/mappings.js b/mappings.js
new file mode 100644
index 00000000..0901159d
--- /dev/null
+++ b/mappings.js
@@ -0,0 +1,3 @@
+export default {
+  function: "_function"
+};
diff --git a/normalizeLineEndings.js b/normalizeLineEndings.js
index 02ee26dd..49fef276 100644
--- a/normalizeLineEndings.js
+++ b/normalizeLineEndings.js
@@ -5,12 +5,12 @@ import path from "path";
 import os from "os";
 import pQueue from "p-queue";
 
+import ignored from "./ignore.js";
+
 const CONCURRENCY = Math.max(1, os.cpus().length - 1);
 
 const { default: PQueue } = pQueue;
 
-import ignored from "./ignore.js";
-
 const [, ignoredDirectories] = ignored;
 
 const {
diff --git a/regenerate.js b/regenerate.js
index 99391995..2cab411c 100644
--- a/regenerate.js
+++ b/regenerate.js
@@ -4,6 +4,7 @@ import { promises } from "fs";
 import path from "path";
 
 import ignored from "./ignore.js";
+import mappings from "./mappings.js";
 
 const [ignoredFiles, ignoredDirectories] = ignored;
 
@@ -11,11 +12,7 @@ const { readdir: readDirectoryAsync, writeFile: writeFileAsync } = promises;
 
 const [, , cwd = process.cwd()] = process.argv;
 
-const mapping = {
-  function: "_function"
-};
-
-const identifier = name => mapping[name] || name;
+const identifier = name => mappings[name] || name;
 
 // Do not match type definition files *.d.ts but match *.ts:
 // https://stackoverflow.com/a/43493203/1384679