react-select-module/src/internal/react-fast-compare.js

A Select control built with and for ReactJS

'use strict';

var isArray = Array.isArray;
var keyList = Object.keys;
var hasProp = Object.prototype.hasOwnProperty;

function equal(a, b) {
  // fast-deep-equal index.js 2.0.1
  if (a === b) return true;

  if (a && b && typeof a == 'object' && typeof b == 'object') {
    var arrA = isArray(a),
      arrB = isArray(b),
      i,
      length,
      key;

    if (arrA && arrB) {
      length = a.length;
      if (length != b.length) return false;
      for (i = length; i-- !== 0; ) {
        if (!equal(a[i], b[i])) return false;
      }
      return true;
    }

    if (arrA != arrB) return false;

    var dateA = a instanceof Date,
      dateB = b instanceof Date;
    if (dateA != dateB) return false;
    if (dateA && dateB) return a.getTime() == b.getTime();

    var regexpA = a instanceof RegExp,
      regexpB = b instanceof RegExp;
    if (regexpA != regexpB) return false;
    if (regexpA && regexpB) return a.toString() == b.toString();

    var keys = keyList(a);
    length = keys.length;

    if (length !== keyList(b).length) {
      return false;
    }

    for (i = length; i-- !== 0; ) {
      if (!hasProp.call(b, keys[i])) return false;
    }
    // end fast-deep-equal

    // Custom handling for React
    for (i = length; i-- !== 0; ) {
      key = keys[i];
      if (key === '_owner' && a.$$typeof) {
        // React-specific: avoid traversing React elements' _owner.
        //  _owner contains circular references
        // and is not needed when comparing the actual elements (and not their owners)
        // .$$typeof and ._store on just reasonable markers of a react element
        continue;
      } else {
        // all other properties should be traversed as usual
        if (!equal(a[key], b[key])) return false;
      }
    }

    // fast-deep-equal index.js 2.0.1
    return true;
  }

  return a !== a && b !== b;
}
// end fast-deep-equal

export default function exportedEqual(a, b) {
  try {
    return equal(a, b);
  } catch (error) {
    if (error.message && error.message.match(/stack|recursion/i)) {
      // warn on circular references, don't crash
      // browsers give this different errors name and messages:
      // chrome/safari: "RangeError", "Maximum call stack size exceeded"
      // firefox: "InternalError", too much recursion"
      // edge: "Error", "Out of stack space"
      console.warn(
        'Warning: react-fast-compare does not handle circular references.',
        error.name,
        error.message
      );
      return false;
    }
    // some other error. we should definitely know about these
    throw error;
  }
}