Nothing Precedes Matter


    1.0.3 • Public • Published


    Promisifies a function that expects a callback with a single (result) argument - in other words, a callback that looks like function(result) { ... } - in what should be a reasonably performant manner.

    Because sometimes, a module just doesn't conform to the Node.js callback convention.


    WTFPL or CC0, whichever you prefer. A donation and/or attribution are appreciated, but not required.


    My income consists largely of donations for my projects. If this module is useful to you, consider making a donation!

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    Pull requests welcome. Please make sure your modifications are in line with the overall code style, and ensure that you're editing the files in src/, not those in lib/.

    Build tool of choice is gulp; simply run gulp while developing, and it will watch for changes.

    Be aware that by making a pull request, you agree to release your modifications under the licenses stated above.


    var Promise = require("bluebird");
    var promisifySimpleCallback = require("promisify-simple-callback");
    /* Pretend that brokenAsyncMethod comes from a third-party library. */
    function brokenAsyncMethod(someArg, options, cb) {
        doSomething(options, function(err, result) {
    /* Promisify it! */
    var promisifiedAsyncMethod = promisifySimpleCallback(brokenAsyncMethod, [null, {}]);
    /* Now we can use it normally. */
    Promise.try(function() {
        return promisifiedAsyncMethod("foobar");
    }).then(function(result) {
        console.log("Done!", result);


    promisifySimpleCallback(func, [defaults])

    Promisifies the given func. The promisified method will also catch any synchronous errors, and propagate them as rejections.

    You can also specify default argument values; often, there are optional arguments that come before the callback, and by specifying default values, you can make these arguments really optional.

    Because promisification works by appending a callback at the end of the arguments list, you would otherwise have to include all the optional arguments just to make sure the callback ends up in the right place.

    • func: The callback-expecting function to promisify.
    • defaults: Optional. An array of default arguments to fill in. Any argument for which you specify null will be skipped - that is, it will be left exactly as is. This means that, for an unspecified argument, it is left to undefined.


    npm i promisify-simple-callback

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    • joepie91