memoize-one/lib/index.js

A memoization library which only remembers the latest invocation

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});

exports.default = function (resultFn) {
  var isEqual = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : simpleIsEqual;

  var lastThis = void 0;
  var lastArgs = [];
  var lastResult = void 0;
  var calledOnce = false;

  var isNewArgEqualToLast = function isNewArgEqualToLast(newArg, index) {
    return isEqual(newArg, lastArgs[index]);
  };

  // breaking cache when context (this) or arguments change
  return function () {
    for (var _len = arguments.length, newArgs = Array(_len), _key = 0; _key < _len; _key++) {
      newArgs[_key] = arguments[_key];
    }

    if (calledOnce && lastThis === this && newArgs.length === lastArgs.length && newArgs.every(isNewArgEqualToLast)) {
      return lastResult;
    }

    calledOnce = true;
    lastThis = this;
    lastArgs = newArgs;
    lastResult = resultFn.apply(this, newArgs);
    return lastResult;
  };
};

var simpleIsEqual = function simpleIsEqual(a, b) {
  return a === b;
};