map-fns/areMapsShallowEqual/index.js

<h1 align="center"> <code>map-fns</code> </h1>

'use strict';

/**
 * Takes in two maps and returns true if they contain the same keys and the
 * values behind their keys are shallowly equal. Returns false otherwise.
 *
 * This function can be useful to check if changes have occurred in any of
 * the items in the map.
 *
 * The order that the maps are provided in does not matter.
 *
 * @param a First map to compare
 * @param b Second map to compare
 * @returns True if they are equal, False if they are not
 */
function areMapsShallowEqual(a, b) {
    var aKeys = Object.keys(a);
    var bKeys = Object.keys(b);
    if (aKeys.length !== bKeys.length) {
        return false;
    }
    for (var i = 0; i < aKeys.length; i += 1) {
        var key = aKeys[i];
        if (!b.hasOwnProperty(key)) {
            return false;
        }
        if (a[key] !== b[key]) {
            return false;
        }
    }
    return true;
}

module.exports = areMapsShallowEqual;