Improve performance more by computing array size

benchmarks/index.ts

@@ -0,0 +1,24 @@
+import sql, { Sql } from "../src/index";
+import bytes from "bytes";
+
+const before = process.memoryUsage();
+console.log(`before: ${bytes(before.heapUsed)} / ${bytes(before.heapTotal)}`);
+const start = process.hrtime();
+
+const queries: Sql[] = [];
+
+for (let i = 0; i < 1_000_000; i++) {
+  const subQuery = `something ${"goes"} here and ${"there"}`;
+  const query = sql`this is ${"the"} query: ${i}, ${subQuery}`;
+  queries.push(query);
+
+  // Compute properties for perf testing.
+  query.text;
+  query.values;
+}
+
+const end = process.hrtime(start);
+const after = process.memoryUsage();
+console.log(`after: ${bytes(after.heapUsed)} / ${bytes(after.heapTotal)}`);
+console.log(`difference: ${bytes(after.heapUsed - before.heapUsed)}`);
+console.log(`time: ${end[0]}s ${~~(end[1] / 1000000)}ms`);

package.json

@@ -8,6 +8,7 @@
     "dist/"
   ],
   "scripts": {
+    "benchmark": "ts-node benchmarks/index.ts",
     "prettier": "prettier --write",
     "lint": "tslint \"src/**/*.ts\" --project tsconfig.json",
     "format": "npm run prettier -- README.md \"{.,src/**/}*.{js,jsx,json,ts,tsx,css,md,yml,yaml}\"",
@@ -76,14 +77,17 @@
     "node": ">=6"
   },
   "devDependencies": {
+    "@types/bytes": "^3.1.0",
     "@types/jest": "^25.2.3",
     "@types/node": "^14.0.5",
+    "bytes": "^3.1.0",
     "husky": "^4.2.5",
     "jest": "^26.0.1",
     "lint-staged": "^10.2.6",
     "prettier": "^2.0.5",
     "rimraf": "^3.0.0",
     "ts-jest": "^26.0.0",
+    "ts-node": "^8.10.1",
     "tslint": "^6.1.2",
     "tslint-config-prettier": "^1.18.0",
     "tslint-config-standard": "^9.0.0",

src/index.spec.ts

@@ -72,7 +72,7 @@ describe("sql template tag", () => {
 
     for (const key in query) keys.push(key);
 
-    expect(keys).toEqual(["rawStrings", "rawValues", "values", "text", "sql"]);
+    expect(keys).toEqual(["values", "strings", "text", "sql"]);
   });
 
   describe("join", () => {

src/index.ts

@@ -7,8 +7,9 @@ export type RawValue = Value | Sql;
  * A SQL instance can be nested within each other to build SQL strings.
  */
 export class Sql {
-  private rawStrings: Array<string>;
-  private rawValues: Array<RawValue>;
+  values: Value[];
+  strings: string[];
+
   constructor(
     rawStrings: ReadonlyArray<string>,
     rawValues: ReadonlyArray<RawValue>
@@ -25,65 +26,47 @@ export class Sql {
       );
     }
 
-    this.rawStrings = [];
-    this.rawValues = [];
+    let valuesLength = rawValues.length;
+    let stringsLength = rawStrings.length;
 
-    if (rawValues.length === 0) {
-      this.rawStrings = rawStrings.slice(0);
-      return;
+    for (const child of rawValues) {
+      if (child instanceof Sql) {
+        valuesLength += child.values.length - 1;
+        stringsLength += child.strings.length - 2;
+      }
     }
 
-    this.rawStrings.length = rawStrings.length;
-
-    if (rawValues.length) {
-      this.rawValues.length = rawValues.length;
+    this.values = new Array(valuesLength);
+    this.strings = new Array(stringsLength);
 
-      for (let child of rawValues) {
-        if (child instanceof Sql) {
-          this.rawStrings.length += child.strings.length;
-          this.rawValues.length += child.values.length - 1;
-        }
-      }
-    }
-    this.rawStrings[0] = rawStrings[0];
+    this.strings[0] = rawStrings[0];
 
-    let i = 1;
-    let strIn = 1;
-    for (; i < rawStrings.length; ++i) {
-      const rawString = rawStrings[i];
-      const child = rawValues[i - 1];
+    // Iterate over raw values, strings, and children. The value is always
+    // positioned between two strings, e.g. `index + 1`.
+    let index = 1;
+    let position = 0;
+    while (index < rawStrings.length) {
+      const child = rawValues[index - 1];
+      const rawString = rawStrings[index++];
 
-      // check for type
+      // Check for nested `sql` queries.
       if (child instanceof Sql) {
-        const len = child.values.length;
-        // concat beginning
-        this.rawStrings[strIn - 1] += child.strings[0];
-
-        for (let d = 0; d < len; ++d) {
-          this.rawStrings[strIn] = child.strings[d + 1];
-          this.rawValues[strIn - 1] = child.values[d];
-          strIn++;
+        // Append child prefix text to current string.
+        this.strings[position] += child.strings[0];
+
+        let childIndex = 0;
+        while (childIndex < child.values.length) {
+          this.values[position++] = child.values[childIndex++];
+          this.strings[position] = child.strings[childIndex];
         }
 
-        // set current
-        this.rawStrings[strIn - 1] += rawString;
+        // Append raw string to current string.
+        this.strings[position] += rawString;
       } else {
-        this.rawStrings[strIn] = rawString;
-        this.rawValues[strIn - 1] = child;
-        ++strIn;
+        this.values[position++] = child;
+        this.strings[position] = rawString;
       }
     }
-
-    this.rawStrings.length = strIn;
-    this.rawValues.length = strIn - 1;
-  }
-
-  get values(): Value[] {
-    return this.rawValues;
-  }
-
-  get strings(): string[] {
-    return this.rawStrings;
   }
 
   get text() {
@@ -106,9 +89,8 @@ export class Sql {
 }
 
 // Work around MySQL enumerable keys in issue #2.
-Object.defineProperty(Sql.prototype, "text", { enumerable: true });
-Object.defineProperty(Sql.prototype, "values", { enumerable: true });
 Object.defineProperty(Sql.prototype, "sql", { enumerable: true });
+Object.defineProperty(Sql.prototype, "text", { enumerable: true });
 
 /**
  * Create a SQL query for a list of values.

tsconfig.json

@@ -9,6 +9,8 @@
     "declaration": true,
     "sourceMap": true,
     "inlineSources": true,
+    "esModuleInterop": true,
     "experimentalDecorators": true
-  }
+  },
+  "include": ["src/**/*"]
 }