Package Exports

run-callback

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Readme

run-callback

Run async or sync callbacks, such as gulp tasks.

The main ideas are borrowed from orchestrator.

run(callback, done)

Run the callback with arguments after callback.

callback

Type: Function

callback can be asynchronous if it does one of the following:

Return a promise

var run = require('run-callback');

run(
  function (a, b, done) {
    return new Promise(function (rs) {
      rs(a + b);
    });
  },
  2, 1,
  function (err, sum) {
    console.log('Expected:', 3);
    console.log('Actual:', sum);
  }
);

Return a stream

var run = require('run-callback');
var Stream = require('stream');

var res = [];
run(
  function (a, b) {
    var rs = Stream.Readable({ objectMode: true });
    var data = [a, b];
    rs._read = function () {
      if (data.length) {
        this.push(data.pop());
      } else {
        this.push(null);
      }
    };
    process.nextTick(function () {
      rs.on('data', function (d) {
        res.push(d);
      });
    });
    return rs;
  },
  1,
  2,
  function (err) {
    console.log('Expected:', [2, 1]);
    console.log('Actual:', res);
  }
);

Accept one more argument than given

That extra argument should be a function.

var run = require('run-callback');

run(
  function (a, b, done) {
    process.nextTick(function () {
      done(null, a + b, a - b);
    });
  },
  2, 1,
  function (err, sum, diff) {
    console.log('Expected:', 3, 1);
    console.log('Actual:', sum, diff);
  }
);

done

Type: Function

Signature: done(err, val1, val2,...)

Synchronous

done will be called when callback finishes.

Errors thrown when executing callback will be passed to done as the first argument, and the return value as the second.

var run = require('run-callback');

run(
  function (a, b) {
    return a + b;
  },
  1, 2,
  function (err, res) {
    console.log('Expected:', 3);
    console.log('Actual:', res);
  }
);

Promisified

done will be called when the returned promise resolves.

Any rejected values will be passed as the first arugment, and any fulfilled values as the second.

Streamified

done will be called when the returned stream ends (readable, transforms, duplex) or finishes (writable).

Errors will be passed as the only arugment.

Other

done will be called when callback invokes the last argument with a possible error object and more values.

done will be called with the same arguments.