fixed-data-table-one.com/internal/ReactComponentWithPureRenderMixin.js

A React table component designed to allow presenting thousands of rows of data.

/**
 * Copyright Schrodinger, LLC
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule ReactComponentWithPureRenderMixin
 */

'use strict';

/**
 * Performs equality by iterating through keys on an object and returning
 * false when any key has values which are not strictly equal between
 * objA and objB. Returns true when the values of all keys are strictly equal.
 *
 * @return {boolean}
 */

function shallowEqual(objA, objB) {
  if (objA === objB) {
    return true;
  }
  var key;
  // Test for A's keys different from B.
  for (key in objA) {
    if (objA.hasOwnProperty(key) && (!objB.hasOwnProperty(key) || objA[key] !== objB[key])) {
      return false;
    }
  }
  // Test for B's keys missing from A.
  for (key in objB) {
    if (objB.hasOwnProperty(key) && !objA.hasOwnProperty(key)) {
      return false;
    }
  }
  return true;
}

/**
 * If your React component's render function is "pure", e.g. it will render the
 * same result given the same props and state, provide this Mixin for a
 * considerable performance boost.
 *
 * Most React components have pure render functions.
 *
 * Example:
 *
 *   var ReactComponentWithPureRenderMixin =
 *     require('ReactComponentWithPureRenderMixin');
 *   React.createClass({
 *     mixins: [ReactComponentWithPureRenderMixin],
 *
 *     render: function() {
 *       return <div className={this.props.className}>foo</div>;
 *     }
 *   });
 *
 * Note: This only checks shallow equality for props and state. If these contain
 * complex data structures this mixin may have false-negatives for deeper
 * differences. Only mixin to components which have simple props and state, or
 * use `forceUpdate()` when you know deep data structures have changed.
 */
var ReactComponentWithPureRenderMixin = {
  shouldComponentUpdate: function shouldComponentUpdate(nextProps, nextState) {
    return !shallowEqual(this.props, nextProps) || !shallowEqual(this.state, nextState);
  }
};

module.exports = ReactComponentWithPureRenderMixin;