olalonde / maybedone

maybe call a callback if predicate returns true of callback called n times

maybedone

Small Node.js helper to wrap callbacks and only call those underlying callback after X times or a predicate function returns true.

install

npm install --save maybedone

usage

maybedone(cb, predicateFn|times)

Arguments:

• cb underlying callback
• predicateFn a function that must return true before cb is called
• times number of times md must be called before the callback is called

Return:

maybedone returns a function md which has the following behavior:

1. When called with an error, md will immediately call the underlying callback with the error.

2. Will always at most call a callback once.

3. Does not throw errors even if it is called too many times.

4. Calls the underlying callback after times times or predicateFn() returns true.

Examples

import maybedone from 'maybedone';
// var maybedone = require('maybedone');

const cb = () => { console.log('done'); };

const md = maybedone(cb, () => {
  return Math.random() > 0.5;
});
// var md = maybdone(cb, function() { /.../ });

md();
md();
md();

import maybedone from 'maybedone';

const cb = () => { console.log('done'); };

const md = maybedone(cb, 3);

md();
md();
md();
// callback fires here
md();
md();
md();

import maybedone from 'maybedone';

const cb = () => { console.log('done'); };

const md = maybedone(cb, 3);

md();
md('someerror');
// callback fires here with error