array-promise-filter

array-promise-filter

Filter an array through async callback. The results can be accessed from the returned promise.

res = filter(values, fn)

var filter = require('array-promise-filter');

values

Type: Array

The array to be filtered.

fn

Type: function

fn should do one of the following.

Respect synchronous signature

fn(val, index, arr)

var filter = require('..');
function isUpperCase(n) {
  return !n.split().some(function (c) {
    return c >= 'a';
  });
}
filter(['ab', 'CD', 'ef', 'GH'], isUpperCase)
  .then(function (res) {
    console.log(res); // ['CD', 'GH']
  })
  .catch(function (err) {
    console.log(err);
  });

Respect asynchronous signature

fn(val, index, arr, next)

next(err, keep) must be called when fn finishes.

var filter = require('..');
function isUpperCase(n, i, arr, next) {
  process.nextTick(function () {
    try {
      next(null, !n.split().some(function (c) {
        return c >= 'a';
      }));
    } catch (e) {
      next(e);
    }
  });
}
filter(['ab', 'CD', 'ef', 'GH'], isUpperCase)
  .then(function (res) {
    console.log(res); // ['CD', 'GH']
  })
  .catch(function (err) {
    console.log(err);
  });

Return a promise

var filter = require('..');
function isUpperCase(n) {
  return new Promise(function (rs, rj) {
    process.nextTick(function () {
      try {
        rs(!n.split().some(function (c) {
          return c >= 'a';
        }));
      } catch (e) {
        rj(e);
      }
    });
  });
}
filter(['ab', 'CD', 'ef', 'GH'], isUpperCase)
  .then(function (res) {
    console.log(res); // ['CD', 'GH']
  })
  .catch(function (err) {
    console.log(err);
  });

res

Type: Promise