date-frequency

frequency

Temporal frequency library

Installation

npm install --save date-frequency

If <=ES5 support is necessary, also install babel-polyfill.

Usage

createFrequency()
  .on('hour', 10)
  .on('minute', 30)
  .next(); // next occurence of 10:30

createFrequency()
  .on('day', 2, 'week')
  .next(); // next Tuesday

// all occurences of 10:00:00 in the next 5 days
const d = new Date();
createFrequency()
  .on('hour', 10)
  .on('m', 0)
  .on('s', 0)
  .between(d, (new Date(+d)).setDate(d.getDate() + 5));

Methods

createFrequency()

Constructor takes a string notation (also see toString()).

createFrequency('F3D/WT10H30M0S');
// every Wednesday at 10:30:00

.on(unit, fix[, scope])

Add frequency rules by specifying a unit and a value to fix it to and an optional scope. The fix parameter can also be an object containing 3 properties: fix, scope and fn.

frequency.on('hour', 10).on('minute', 0).on('second', 0);
// each day at 10:00:00

frequency.on('day', 6).on('m', 30);
// each 30 minutes after the hour of the 6th day of each month

frequency.on('d', 7, 'week');
// Sundays at midnight

Frequency.fn.even = require('number-kind').even;
frequency.on('week', {fn: 'even', scope: 'epoch'}).on('h', 0).on('m', 0).on('s', 0);
// days of even weeks at midnight

.next(date)

Returns the next occurence of the frequency on or after the specified date. Please note that you are responsible for incrementing the date if you want to call .next() multiple times to get consecutive occurences.

.between(start, end)

Returns all occurences of the frequency between (and including) the specified start and end date.

.toString()

Returns a string notation of the frequency.

Development

• Clone repo & npm install.
• Lint: npm run lint.
• Test: npm test.