exported promisify method;

added `CanceledError.rethrow` method; all static methods lazily bound to the constructor context;
DigitalBrainJS · Dec 12, 2020 · 8c9746b · 8c9746b
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -6,6 +6,15 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 For changes before version 0.4.0, please see the commit history
 
+## [0.10.8] - 2020-12-13
+
+### Added
+- exported `promisify` method;
+- `CanceledError.rethrow` method;
+
+### Updated
+- all static methods lazily bound to the constructor context;
+
 ## [0.10.7] - 2020-12-12
 
 ### Added

diff --git a/README.md b/README.md
@@ -406,33 +406,37 @@ Check out this [live demo](https://codesandbox.io/s/infallible-ardinghelli-7r6o8
 }
 ````
 #### React functional component
-Using hooks and CPromise `cancel` method [Live Demo](https://codesandbox.io/s/react-cpromise-fetch-kydim?file=/src/MyComponent.js):
+Using hooks and CPromise `cancel` method [Live Demo](https://codesandbox.io/s/react-cpromise-fetch-promisify-forked-3h4v2?file=/src/MyComponent.js):
 ````jsx
 import React, { useEffect, useState } from "react";
-import CPromise from "c-promise2";
+import { CPromise, CanceledError } from "c-promise2";
 import cpFetch from "cp-fetch";
 
 function MyComponent(props) {
-    const [text, setText] = useState("fetching...");
-
-    useEffect(() => {
-        console.log("mount");
-        const promise = cpFetch(props.url)
-            .then((response) => response.json())
-            .then((value) => CPromise.delay(1000, value))
-            .then((json) => setText(`Success: ${JSON.stringify(json)}`))
-            .canceled() // catch CanceledError
-            .catch((err) => {
-                setText(`Failed: ${err}`);
-            });
-
-        return () => {
-            console.log("unmount");
-            promise.cancel();
-        };
-    }, [props.url]);
-
-    return <p>{text}</p>;
+  const [text, setText] = useState("fetching...");
+
+  useEffect(() => {
+    console.log("mount");
+    const promise = CPromise.from(function* () {
+      try {
+        const response = yield cpFetch(props.url);
+        const json = yield response.json();
+        yield CPromise.delay(1000);
+        setText(`Success: ${JSON.stringify(json)}`);
+      } catch (err) {  
+        console.warn(err);
+        CanceledError.rethrow(err);
+        setText(`Failed: ${err}`);
+      }
+    });
+
+    return () => {
+      console.log("unmount");
+      promise.cancel();
+    };
+  }, [props.url]);
+
+  return <p>{text}</p>;
 }
 ````
 #### React class component with CPromise decorators
@@ -824,6 +828,10 @@ label decorator
 ### CPromise.progress : <code>function</code>
 progress decorator
 
+**Kind**: static property of [<code>CPromise</code>](#module_CPromise)  
+<a name="module_CPromise.promisify"></a>
+
+### CPromise.promisify : <code>function</code>
 **Kind**: static property of [<code>CPromise</code>](#module_CPromise)  
 <a name="module_CPromise..CPromise"></a>
 

diff --git a/jsdoc2md/README.hbs.md b/jsdoc2md/README.hbs.md
@@ -406,33 +406,37 @@ Check out this [live demo](https://codesandbox.io/s/infallible-ardinghelli-7r6o8
 }
 ````
 #### React functional component
-Using hooks and CPromise `cancel` method [Live Demo](https://codesandbox.io/s/react-cpromise-fetch-kydim?file=/src/MyComponent.js):
+Using hooks and CPromise `cancel` method [Live Demo](https://codesandbox.io/s/react-cpromise-fetch-promisify-forked-3h4v2?file=/src/MyComponent.js):
 ````jsx
 import React, { useEffect, useState } from "react";
-import CPromise from "c-promise2";
+import { CPromise, CanceledError } from "c-promise2";
 import cpFetch from "cp-fetch";
 
 function MyComponent(props) {
-    const [text, setText] = useState("fetching...");
-
-    useEffect(() => {
-        console.log("mount");
-        const promise = cpFetch(props.url)
-            .then((response) => response.json())
-            .then((value) => CPromise.delay(1000, value))
-            .then((json) => setText(`Success: ${JSON.stringify(json)}`))
-            .canceled() // catch CanceledError
-            .catch((err) => {
-                setText(`Failed: ${err}`);
-            });
-
-        return () => {
-            console.log("unmount");
-            promise.cancel();
-        };
-    }, [props.url]);
-
-    return <p>{text}</p>;
+  const [text, setText] = useState("fetching...");
+
+  useEffect(() => {
+    console.log("mount");
+    const promise = CPromise.from(function* () {
+      try {
+        const response = yield cpFetch(props.url);
+        const json = yield response.json();
+        yield CPromise.delay(1000);
+        setText(`Success: ${JSON.stringify(json)}`);
+      } catch (err) {  
+        console.warn(err);
+        CanceledError.rethrow(err);
+        setText(`Failed: ${err}`);
+      }
+    });
+
+    return () => {
+      console.log("unmount");
+      promise.cancel();
+    };
+  }, [props.url]);
+
+  return <p>{text}</p>;
 }
 ````
 #### React class component with CPromise decorators

diff --git a/lib/c-promise.js b/lib/c-promise.js
@@ -1891,6 +1891,31 @@ Object.entries(decorators).forEach(([name, initializer]) => {
     })
 })
 
+const lazyBindMethods = (obj, props) => {
+    props.forEach(prop => {
+        const symbol = Symbol(`${prop}Bound`);
+        const {value: fn} = Object.getOwnPropertyDescriptor(obj, prop);
+
+        Object.defineProperty(obj, prop, {
+            get: function () {
+                return this[symbol] || (this[symbol] = fn.bind(this))
+            },
+
+            set: function (v) {
+                throw Error(`Can not rewrite method ${prop} with ${v}`);
+            },
+
+            enumerable: true,
+            configurable: true
+        })
+    })
+}
+
+lazyBindMethods(CPromise, Object.getOwnPropertyNames(CPromise).map(prop => {
+    const {value} = Object.getOwnPropertyDescriptor(CPromise, prop);
+    return typeof value === 'function' ? prop : '';
+}).filter(Boolean));
+
 exports.CPromise = CPromise;
 /**
  * CanceledError class
@@ -1961,3 +1986,7 @@ exports.canceled = CPromise.canceled;
  * @type {Function}
  */
 exports.progress = CPromise.progress;
+/**
+ * @type {Function}
+ */
+exports.promisify = CPromise.promisify;
diff --git a/lib/canceled-error.js b/lib/canceled-error.js
@@ -2,39 +2,39 @@
  * @module CanceledError
  */
 
-const _scope= Symbol('scope');
-const _errors= Symbol('errors');
-const _code= Symbol('code');
+const _scope = Symbol('scope');
+const _errors = Symbol('errors');
+const _code = Symbol('code');
 
 /**
  * CanceledError
  */
 
-class CanceledError extends Error{
+class CanceledError extends Error {
     /**
      * Constructs a new error instance
      * @param {String} reason
      */
-    constructor(reason= E_REASON_CANCELED) {
+    constructor(reason = E_REASON_CANCELED) {
         super();
-        this.name= this.constructor.name;
-        const registered= this.constructor[_errors][reason];
-        if(registered){
-            this.message= registered;
-            this[_code]= reason;
-        }else{
-            this.message= reason;
+        this.name = this.constructor.name;
+        const registered = this.constructor[_errors][reason];
+        if (registered) {
+            this.message = registered;
+            this[_code] = reason;
+        } else {
+            this.message = reason;
         }
 
-        this[_scope]= null;
+        this[_scope] = null;
     }
 
     /**
      * get promise scope where the error was raised
      * @returns {CPromise|null}
      */
 
-    get scope(){
+    get scope() {
         return this[_scope];
     }
 
@@ -43,13 +43,13 @@ class CanceledError extends Error{
      * @returns {string}
      */
 
-    get code(){
+    get code() {
         return this[_code] || '';
     }
 
-    set scope(scope){
-        if(!this[_scope]){
-            this[_scope]= scope;
+    set scope(scope) {
+        if (!this[_scope]) {
+            this[_scope] = scope;
             return;
         }
         throw Error('Scope has been already set');
@@ -87,30 +87,54 @@ class CanceledError extends Error{
      * @returns {boolean}
      */
 
-    static isCanceledError(thing){
+    static isCanceledError(thing) {
         return thing instanceof this;
     }
 
-    static registerErrors(errors){
-       return Object.entries(errors).reduce((acc, [name, message])=>{
-           Object.defineProperty(this, name, {
-               value: name
-           });
-           this[_errors][name]= message;
-           acc[name]= name;
-           return acc;
-       }, {});
+    static registerErrors(errors) {
+        return Object.entries(errors).reduce((acc, [name, message]) => {
+            Object.defineProperty(this, name, {
+                value: name
+            });
+            this[_errors][name] = message;
+            acc[name] = name;
+            return acc;
+        }, {});
+    }
+
+    /**
+     * Rethrow the canceled error with optional codes matching
+     * @param err an error to assert
+     * @param {...String} [codes]
+     * @throws CanceledError
+     */
+
+    static rethrow(err, ...codes) {
+        const {length} = codes;
+        if (!(err instanceof CanceledError)) {
+            return;
+        }
+        if (!length) {
+            throw err;
+        } else {
+            const {code} = err;
+            for (let i = 0; i < length; i++) {
+                if (codes[i] === code) {
+                    throw err;
+                }
+            }
+        }
     }
 }
 
-CanceledError[_errors]= {};
+CanceledError[_errors] = {};
 
-const {E_REASON_CANCELED}= CanceledError.registerErrors({
-    E_REASON_CANCELED : 'canceled',
-    E_REASON_TIMEOUT : 'timeout',
-    E_REASON_DISPOSED : 'disposed'
+const {E_REASON_CANCELED} = CanceledError.registerErrors({
+    E_REASON_CANCELED: 'canceled',
+    E_REASON_TIMEOUT: 'timeout',
+    E_REASON_DISPOSED: 'disposed'
 });
 
-module.exports= {
+module.exports = {
     CanceledError
 };