Package Exports

nextframe

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (nextframe) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

nextframe

Promise for requestAnimationFrame / plus features like nextFrames, frameSequence, delay, throttleFrames, waitFrames

usage

const { nextFrame, nextFrames, sequence, delay, throttleFrames, waitFrames } = require('./lib');
const now = require('performance-now');

const increment = val => ++val;

const sequenceValues = [1, 2, 3, 4];
let frameCount = 0;
let throttleCount = 0;

const start = now();

/****************************
        nextFrame
****************************/
nextFrame()
  .then(() => {
    console.log('next frame');
  })

/****************************
        delay
****************************/
delay(1000).then(() => {
  console.log('delayed ' + (now() - start) + 'ms');
});

/****************************
        sequence / frameSequence
****************************/
sequence(sequenceValues, increment)
  .then(result => console.log(result));

/****************************
        nextFrames
****************************/
const cancelNext = nextFrames(() => {
  console.log('frame', ++frameCount);
  if (frameCount >= 100) {
    cancelNext();
  }
});

/****************************
        throttleFrames
****************************/
const cancelThrottle = throttleFrames(() => {
  console.log('throttle', ++throttleCount);
  if (throttleCount >= 10) {
    cancelThrottle();
  }
}, 10);

/****************************
        waitFrames
****************************/
waitFrames(50).then((count) => {
  console.log(count + ' frames waited');
})

tests

(passing)

import test from 'ava';
import now from 'performance-now';

import nextFrame, { nextFrames, delay, sequence, waitFrames, throttleFrames } from './lib';

test('call next frame with argument', async t => {
  const value = await nextFrame('check');
  t.is(value, 'check');
});

test('delay 1s', async t => {
  const start = now();
  const value = await delay(1000, 'check');
  const duration = now() - start;
  t.is(value, 'check');
  t.truthy(duration >= 1000 && duration <= 1100);
});

test('sequence', async t => {
  const values = [1, 2, 3, 4];
  const increment = val => ++val;
  const result = await sequence(values, increment);
  t.deepEqual(result, [2, 3, 4, 5]);
});

test('nextFrames loop', async t => {
  const p = new Promise(resolve => {
    let i = 0;
    const cancel = nextFrames(() => {
      ++i;
      if (i >= 20) {
        cancel();
        resolve(20);
      }
    })
  })
  const result = await p;
  t.is(result, 20);
});

test('wait 50 frames', async t => {
  let i = 0;
  const cancel = nextFrames(() => ++i);

  const result = await waitFrames(50);

  cancel();
  t.is(result, 50);
  t.is(i, 50);
});

test('throttle frames', async t => {
  let i = 0;
  let throttleCount = 0;

  const p = new Promise(resolve => {
    const cancel = nextFrames(() => ++i);

    const cancelThrottle = throttleFrames(() => {
      if (++throttleCount >= 10) {
        cancelThrottle();
        cancel();
        resolve(throttleCount)
      }
    }, 10);
  });
  const result = await p;
  t.is(result, 10);
  t.is(i, 100);
});