index.js

/**
 * Module dependencies.
 */

var visit = require('rework-visit');

/**
 * Easing functions.
 */

var ease = {
  'ease-in-out-back': 'cubic-bezier(0.680, -0.550, 0.265, 1.550)',
  'ease-in-out-circ': 'cubic-bezier(0.785, 0.135, 0.150, 0.860)',
  'ease-in-out-expo': 'cubic-bezier(1.000, 0.000, 0.000, 1.000)',
  'ease-in-out-sine': 'cubic-bezier(0.445, 0.050, 0.550, 0.950)',
  'ease-in-out-quint': 'cubic-bezier(0.860, 0.000, 0.070, 1.000)',
  'ease-in-out-quart': 'cubic-bezier(0.770, 0.000, 0.175, 1.000)',
  'ease-in-out-cubic': 'cubic-bezier(0.645, 0.045, 0.355, 1.000)',
  'ease-in-out-quad': 'cubic-bezier(0.455, 0.030, 0.515, 0.955)',
  'ease-out-back': 'cubic-bezier(0.175, 0.885, 0.320, 1.275)',
  'ease-out-circ': 'cubic-bezier(0.075, 0.820, 0.165, 1.000)',
  'ease-out-expo': 'cubic-bezier(0.190, 1.000, 0.220, 1.000)',
  'ease-out-sine': 'cubic-bezier(0.390, 0.575, 0.565, 1.000)',
  'ease-out-quint': 'cubic-bezier(0.230, 1.000, 0.320, 1.000)',
  'ease-out-quart': 'cubic-bezier(0.165, 0.840, 0.440, 1.000)',
  'ease-out-cubic': 'cubic-bezier(0.215, 0.610, 0.355, 1.000)',
  'ease-out-quad': 'cubic-bezier(0.250, 0.460, 0.450, 0.940)',
  'ease-in-back': 'cubic-bezier(0.600, -0.280, 0.735, 0.045)',
  'ease-in-circ': 'cubic-bezier(0.600, 0.040, 0.980, 0.335)',
  'ease-in-expo': 'cubic-bezier(0.950, 0.050, 0.795, 0.035)',
  'ease-in-sine': 'cubic-bezier(0.470, 0.000, 0.745, 0.715)',
  'ease-in-quint': 'cubic-bezier(0.755, 0.050, 0.855, 0.060)',
  'ease-in-quart': 'cubic-bezier(0.895, 0.030, 0.685, 0.220)',
  'ease-in-cubic': 'cubic-bezier(0.550, 0.055, 0.675, 0.190)',
  'ease-in-quad': 'cubic-bezier(0.550, 0.085, 0.680, 0.530)'
};

/**
 * Keys.
 */

var keys = Object.keys(ease);

/**
 * Provide additional easing functions:
 *
 *    #logo {
 *      transition: all 500ms ease-out-back;
 *    }
 *
 * yields:
 *
 *    #logo {
 *      transition: all 500ms cubic-bezier(0.175, 0.885, 0.320, 1.275)
 *    }
 *
 */

module.exports = function() {
  return function(style){
    visit(style, substitute);
  }
};

/**
 * Substitute easing functions.
 *
 * @api private
 */

function substitute(declarations) {
  for (var i = 0, len = declarations.length; i < len; ++i) {
    var decl = declarations[i];
    if ('comment' == decl.type) continue;
    if (!decl.property.match(/transition|animation|timing/)) continue;
    for (var k = 0; k < keys.length; ++k) {
      var key = keys[k];
      if (~decl.value.indexOf(key)) {
        decl.value = decl.value.replace(key, ease[key]);
        break;
      }
    }
  }
}