forked from arne/asdf-games
2.5 KiB
2.5 KiB
es6-promisify
Converts callback-based functions to ES6/ES2015 Promises, using a boilerplate callback function.
NOTE: All-new API for Version 6.0.0; please read carefully!
Install
Install with npm
npm install es6-promisify
Example
const {promisify} = require("es6-promisify");
// Convert the stat function
const fs = require("fs");
const stat = promisify(fs.stat);
// Now usable as a promise!
stat("example.txt").then(function (stats) {
console.log("Got stats", stats);
}).catch(function (err) {
console.error("Yikes!", err);
});
Promisify methods
const {promisify} = require("es6-promisify");
// Create a promise-based version of send_command
const redis = require("redis").createClient(6379, "localhost");
const client = promisify(redis.send_command.bind(redis));
// Send commands to redis and get a promise back
client("ping").then(function (pong) {
console.log("Got", pong);
}).catch(function (err) {
console.error("Unexpected error", err);
}).then(function () {
redis.quit();
});
Handle multiple callback arguments, with named parameters
const {promisify} = require("es6-promisify");
function test(cb) {
return cb(undefined, 1, 2, 3);
}
// Create promise-based version of test
test[promisify.argumentNames] = ["one", "two", "three"];
const multi = promisify(test);
// Returns named arguments
multi().then(result => {
console.log(result); // {one: 1, two: 2, three: 3}
});
Provide your own Promise implementation
const {promisify} = require("es6-promisify");
// Now uses Bluebird
promisify.Promise = require("bluebird");
const test = promisify(cb => cb(undefined, "test"));
test().then(result => {
console.log(result); // "test", resolved using Bluebird
});
Tests
Test with tape
$ npm test
Changes from v5.0.0
- Allow developer to specify a different implementations of
Promise
- No longer ships with a polyfill for
Promise
. If your environment has no nativePromise
you must polyfill yourself, or setpromisify.Promise
to an A+ compatiblePromise
implementation. - Removed support for
settings.thisArg
: use.bind()
instead. - Removed support for
settings.multiArgs
: use named arguments instead.
Published under the MIT License.