1'use strict'; 2 3var keys = require('object-keys'); 4var hasSymbols = typeof Symbol === 'function' && typeof Symbol('foo') === 'symbol'; 5 6var toStr = Object.prototype.toString; 7var concat = Array.prototype.concat; 8var origDefineProperty = Object.defineProperty; 9 10var isFunction = function (fn) { 11 return typeof fn === 'function' && toStr.call(fn) === '[object Function]'; 12}; 13 14var arePropertyDescriptorsSupported = function () { 15 var obj = {}; 16 try { 17 origDefineProperty(obj, 'x', { enumerable: false, value: obj }); 18 // eslint-disable-next-line no-unused-vars, no-restricted-syntax 19 for (var _ in obj) { // jscs:ignore disallowUnusedVariables 20 return false; 21 } 22 return obj.x === obj; 23 } catch (e) { /* this is IE 8. */ 24 return false; 25 } 26}; 27var supportsDescriptors = origDefineProperty && arePropertyDescriptorsSupported(); 28 29var defineProperty = function (object, name, value, predicate) { 30 if (name in object && (!isFunction(predicate) || !predicate())) { 31 return; 32 } 33 if (supportsDescriptors) { 34 origDefineProperty(object, name, { 35 configurable: true, 36 enumerable: false, 37 value: value, 38 writable: true 39 }); 40 } else { 41 object[name] = value; 42 } 43}; 44 45var defineProperties = function (object, map) { 46 var predicates = arguments.length > 2 ? arguments[2] : {}; 47 var props = keys(map); 48 if (hasSymbols) { 49 props = concat.call(props, Object.getOwnPropertySymbols(map)); 50 } 51 for (var i = 0; i < props.length; i += 1) { 52 defineProperty(object, props[i], map[props[i]], predicates[props[i]]); 53 } 54}; 55 56defineProperties.supportsDescriptors = !!supportsDescriptors; 57 58module.exports = defineProperties; 59