# wrap-as-async > Utility method to wrap a function into an asynchronous method using the common this.async() style. Latest version **1.3.1** (published 2016-08-30) · MIT license · 0 weekly downloads ## Install ```sh npm install wrap-as-async pnpm add wrap-as-async yarn add wrap-as-async bun add wrap-as-async ``` ## Health **Score 15/100 (F)** — status: abandoned. Positive: no vulnerabilities. Warnings: low downloads; no types; no esm support. Negative: abandoned; low maintenance score. ## Facts | | | |---|---| | Version | 1.3.1 | | Published | 2016-08-30 | | First published | 2015-10-24 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | none | | Module format | CommonJS | | Node | >=0.10.0 | | Dependencies | 0 | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 0 | | Author | kaelzhang | | Maintainers | kael | | Keywords | wrap-as-async, wrap, async, this.async(), run, run-async | ## Links - npm: https://www.npmjs.com/package/wrap-as-async - Repository: https://github.com/kaelzhang/wrap-as-async - Homepage: https://github.com/kaelzhang/wrap-as-async#readme - Issues: https://github.com/kaelzhang/wrap-as-async/issues - npm.io page: https://npm.io/package/wrap-as-async ## Alternatives - [@mce/gif](https://npm.io/package/@mce/gif.md) — 2.6K weekly downloads - [cleanse](https://npm.io/package/cleanse.md) — 173 weekly downloads - [str](https://npm.io/package/str.md) — 127 weekly downloads - [naming](https://npm.io/package/naming.md) — 95 weekly downloads - [tap-telco-api](https://npm.io/package/tap-telco-api.md) — 19 weekly downloads ## Recent versions - 1.3.1 (latest) — 2016-08-30 - 1.3.0 — 2016-08-30 - 1.2.2 — 2015-12-04 - 1.2.1 — 2015-11-21 - 1.2.0 — 2015-11-21 - 1.1.8 — 2015-11-21 - 1.1.7 — 2015-11-08 - 1.1.6 — 2015-11-08 - 1.1.5 — 2015-11-08 - 1.1.4 — 2015-10-28 - 1.1.3 — 2015-10-28 - 1.1.2 — 2015-10-28 - 1.1.1 — 2015-10-28 - 1.1.0 — 2015-10-28 - 1.0.5 — 2015-10-27 - … 5 more at https://npm.io/package/wrap-as-async/versions ## README [![Build Status](https://travis-ci.org/kaelzhang/wrap-as-async.svg?branch=master)](https://travis-ci.org/kaelzhang/wrap-as-async) # wrap-as-async Utility method to - wrap a function which returns a `Promise` into a normal asynchronous function. - wrap a function into an asynchronous method using the common `this.async()` style, with browser compatibility. ## Install ```sh $ npm install wrap-as-async --save ``` ## Synopsis ```js var wrap = require('wrap-as-async'); // Wrap a synchronous function into an asynchronous one. // Or wrap a function that using the `this.async()` style // into a normal asynchronous function. // `wrapped` is an asynchronous function. var wrapped = wrap(fn); // The return value of function `wrapped` indicates // whether the original function is asynchronous, // which might be useful. var is_async = wrapped(args, function(err, result){ // The callback of either sync or async function // will always has the `err` as the first argument. }); ``` #### Wrap a sync method into async ```js var wrapped = wrap(function (n){ return n + 1; }); var is_async = wrapped(1, function(err, result){ console.log(err); // null console.log(result); // 2 }); is_async; // false ``` #### Wrap an async function using `this.async()` ```js var wrapped = wrap(function(n){ var done = this.async(); setTimeout(function(){ if (n < 0) { return done(new Error('n should not less than 0')); } done(null, n + 1); }, 10) }); var is_async = wrapped(1, function(err, result){ console.log(err); // null console.log(result); // 2 }); is_async; // true wrapped(-1, function(err){ console.log(err); // Error }); ``` #### Handles `this` object `wrap-as-async` handles `this` object, so the `wrap()`ped function could be assigned onto function prototypes, instances or singletons, acting like a decorator(such as python decorators), which will be really helpful. ```js function myClass (decorate) { this.decorate = wrap(decorate); } myClass.prototype.method = wrap(method); ``` And also could assign `this` object by using `call`: ```js wrap(function(n){ return n + this.base }).call({ base: 2 }, 1, function(err, result){ // result -> 3 }); wrap(function(n){ // You could still use `this.async()` even with `call` var done = this.async(); var base = this.base; setTimeout(function(){ done(null, n + base) }, 10) }).call({ base: 2 }, 1, function(err, result){ // result -> 3 }); ``` #### Multiple arguments and `done` result ```js wrap(function(n, m){ var done = this.async(); done(null, n + 1, m + 1); })(1, 2, function(err, result1, result2){ // result1 -> 2 // result2 -> 3 }); ``` ## Synchronous and asynchronous Methods ```js function sync_method (arg...){ return something } ``` If the method to be wrapped returns an instance of `Error`, it will be treated as a failure instead, or the `returnValue` will be the result. ```js function async_method (arg...) { var done = this.async(); someAsyncProcess(function(...){ ... done(err, result); }); } ``` You could use `this.async()` to turn the method into an asynchonous method, and `this.async` will return the callback function. ## `Promise` support ```js wrap(function(n){ return Promise.resolve(n + 1) })(1, (err, result) => { // result -> 2 }) ``` ## License MIT --- _Source: https://npm.io/package/wrap-as-async · Machine-readable twin of the npm.io package page. 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