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thenify

3.3.0 • Public • Published

thenify

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Promisify a callback-based function using any-promise.

  • Preserves function names
  • Uses a native promise implementation if available and tries to fall back to a promise implementation such as bluebird
  • Converts multiple arguments from the callback into an Array, also support change the behavior by options.multiArgs
  • Resulting function never deoptimizes
  • Supports both callback and promise style

An added benefit is that thrown errors in that async function will be caught by the promise!

API

fn = thenify(fn, options)

Promisifies a function.

Options

options are optional.

  • options.withCallback - support both callback and promise style, default to false.

  • options.multiArgs - change the behavior when callback have multiple arguments. default to true.

    • true - converts multiple arguments to an array
    • false- always use the first argument
    • Array - converts multiple arguments to an object with keys provided in options.multiArgs
  • Turn async functions into promises

var thenify = require('thenify');
 
var somethingAsync = thenify(function somethingAsync(a, b, c, callback) {
  callback(null, a, b, c);
});
  • Backward compatible with callback
var thenify = require('thenify');
 
var somethingAsync = thenify(function somethingAsync(a, b, c, callback) {
  callback(null, a, b, c);
}, { withCallback: true });
 
// somethingAsync(a, b, c).then(onFulfilled).catch(onRejected);
// somethingAsync(a, b, c, function () {});

or use thenify.withCallback()

var thenify = require('thenify').withCallback;
 
var somethingAsync = thenify(function somethingAsync(a, b, c, callback) {
  callback(null, a, b, c);
});
 
// somethingAsync(a, b, c).then(onFulfilled).catch(onRejected);
// somethingAsync(a, b, c, function () {});
  • Always return the first argument in callback
var thenify = require('thenify');
 
var promise = thenify(function (callback) {
  callback(null, 1, 2, 3);
}, { multiArgs: false });
 
// promise().then(function onFulfilled(value) {
//   assert.equal(value, 1);
// });
  • Converts callback arguments to an object
var thenify = require('thenify');
 
var promise = thenify(function (callback) {
  callback(null, 1, 2, 3);
}, { multiArgs: [ 'one', 'tow', 'three' ] });
 
// promise().then(function onFulfilled(value) {
//   assert.deepEqual(value, {
//     one: 1,
//     tow: 2,
//     three: 3
//   });
// });

install

npm i thenify

Downloadsweekly downloads

498,405

version

3.3.0

license

MIT

homepage

github.com

repository

Gitgithub

last publish

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