ParallaxBro

const ParallaxBro = require('parallaxbro');
const laxbro = new ParallaxBro('#wrapper', '2000px');

const c1 = laxbro.addCollection('#collection1');

c1.addElements({
  '#element1': {
    top: 100, // All position values are assumed to be in px.
    hide: {0: false, 500: true}, // Will hide once window.pageYOffset ≈ 500px.
    center: true, // Applies 'margin: 0 auto'
    speed: {
      0: 1, // Speed 1 is normal scrolling rate.
      500: 0, // Speed 0 will stop the element from scrolling.
      1000: -1, // Negative values scroll the element in reverse.
    }
    zIndex: -1, // -1 is default zIndex for all elements.
    update: {
      0: ($el, posY) => $el.fadeOut(), // $el is jQuery wrapped element.
      1000: ($el, posY) => $el.fadeIn(), // Called when window.pageYOffset ≈ 1000.
    },
    xFunc: (posY) => posY, // Changes the element's x position.
  },
  '#element2': { /* ... */ }
});

Installing

Npm:

npm i --save parallaxbro

Manually:

Find the library at: ./dist/index.js and ./dist/index.min.js

* jQuery is a required dependency

Demo

https://iamdevonbutler.github.io/parallaxbro/

See App.js to view the demo's parallaxbro config.

Collections and elements

Parallax elements are grouped into collections. A collection is a convenient way to apply behaviors to a group of elements. Properties such as: top, and hide, are applied to all elements in a collection. Collections are a useful in the development of parallax designs; for instance, they offer a convenient way to either hide or position sections of your content.

Multi parameter objects

In the example above, the hide and speed options accept both simple Boolean / Number values or a keyed object. The object keys, we call them breakpoints, change the behavior of your program when the pageYOffset position is == the breakpoint. Object values for options can be passed to both collections and elements.

c1.addElement('#wrapper', {
  top: {
    0: 0,
    500: 100,
    1000: 1000,
  },
  hide: {
    0: false,
    1500: true,
  }
})

The speed option

Setting the speed option to 1 will have no effect on the element. It will scroll w/ the page per normal.

Setting the speed option to a negative value will move the element in the reverse direction.

Setting the speed option to 0 will freeze the element on the page.

Custom updates

Leverage the update option to preform updates of any sort at specific breakpoints:

const c1 = require('./collection');

c1.addElements('#element1', {
 /**
  * @param {Object} $el - element wrapped in jQuery
  * @param {Number} posY
  * @this - the parallax element.
  */
  update: {
    0: ($el, posY) => $el.fadeOut()
    200: ($el, posY) => $el.fadeIn()
  }
});

xFunc

The xFunc option for parallax elements allows you to move elements on the x-axis in addition to the y-axis.

const c1 = require('./collection');

c1.addElements('#element1', {
   /**
    * @param {Number} posY
    */     
    xFunc: {
      1200: (posY) => -posY
    },
});

The callback is passed posY (pageYOffset - breakpoint), and the function should return the element's new x position.

Debug mode

Pass the option debug=true to add a window.pageYOffset indicator to the page.

API

ParallaxBro(selector, height, [options]) - constructor.

@param {String} selector

Selector string of the wrapper element.

@param {Number} height

Static height of the parallax page. It's useful to set it to a large number in development and change it once your design is completed.

@param {Object} [options]

• debug {Boolean} - adds a debugger to the page.
• disableStyles {Boolean} - disable ParallaxBro default page styling.
• height {String} - parallax page height.

.addCollection(selector, [options])

const ParallaxBro = require('parallaxbro');
const laxbro = new ParallaxBro('#wrapper');

const c1 = laxbro.addCollection('#collection1', {});

@param {String} selector Selector string of the collection wrapper element.

@param {Object} [options]

Options include:

• top {Number|Object}
• hide {Boolean|Object}
• zIndex {Number|Object}
• update {Object}

.addElements(obj)

const c1 = require('./collection');

c1.addElements({
  '#elementSelector': { /* options */ },
  '#elementSelector2': { /* options */ },
});

@param {Object} options

Options include:

• top {Number|Object}
• hide {Boolean|Object}
• speed {Number|Object}
• center {Boolean|Object}
• zIndex {Number|Object}
• update {Object}
• xFunc {Function|Object}

.addElement(selector, obj)

const c1 = require('./collection');

c1.addElement('#elementSelector', {
  /* options */
});

@param {String} selector

Selector string of the element.

@param {Object} options

Options are the same as .addElements()

.unbind()

Unbinds Parallaxbro from requestAnimationFrame recused loop.