number-transition v0.1.0

Overview

Transition from one number to another during a given duration.

var transition = require("number-transition")

function tick(fn) { setTimeout(fn, 20) }

transition(tick, {from: 1, to: 5, duration: 100, step: console.log})

// Something like the following will be logged at an interval of about 20ms:
// 3.0700000000000003
// 5.2299999999999995
// 7.12
// 9.01
// 10

Inspired by kamicane/transtion, but more transition-like than animation-like, with better browser support and no dependencies.

Installation

npm install number-transititon

var transition = require("number-transititon")

// Possibly:
var transition = require("number-transititon").bind(null, requestAnimationFrame)

Usage

var abort = transition(tick, options, [callback])

transition transitions from options.from to options.to in options.duration milliseconds by calling options.step(value) each tick, where value is the current transitional value. By default the transition is linear, but that can be changed by passing a different timing function as options.timing.

tick(fn) is an asyncronous function that calls fn. requestAnimationFrame is a good choice. tick is the first argument (and not an option), so that you could easily .bind() it (as in the example above).

options:

• from: Number. Defaults to 0.
• to: Number. Defaults to 1.
• timing: Function. Defaults to a linear function. It receives the amount of elapsed time as a number from 0 to 1. It should return a number as well.
• duration: Number. Required. The number of milliseconds that the transition should last. The transition runs at least this many milliseconds, but may run for longer depending on how tick is implemented.
• step: Function. Required. Receives the current transitional value and lets you do something with it.

If available, callback(false) is called when the transition finishes.

Calling the returned abort function aborts the transition and calls callback(true). (In other words, the argument passed to callback indicates whether the transition was aborted or not.)

License

The X11 (“MIT”) License.