es5 api

ES5

• Object.create(prototype, descriptors)

  //创建对象
  var o1 = {foo:'bar'};
  var o2 = new Object();
  //Object.create(proto,[descriptors]);
  var o3 = Object.create(null);

  function Person(name) {
  this.name = name;
  }
  var p1 = new Person('sindy');
  var p2 = Object.create(Person.prototype, {
  age: {
  value: 18,
  writable: false,
  enumerable: false,
  configurable: true,
  //value , writable 和 getter setter函数不能同时设置
  /get: function () {
  if (typeof age === 'undefined') {
  return 'not set age value yet';
  } else {
  return 'your age:' + age;
  }
  },
  set: function (a) {
  age = a;
  if (this.cTime == 0) {
  console.log('set age OK');
  this.cTime++;
  } else {
  console.log('change age OK');
  }
  }
  },/
  cTime: {
  value: 0,
  writable: true
  }
  });

• Object.defineProperty(object, propertyName, descriptor)

  var p1 = new Person('alice');
  Object.defineProperty(p1, 'name', {value:'alice2', writable:true, enumerable: false, configurable: false});
  console.log(p1.name); //=> alice2
  delete p1.name; //=> false

  configurable==flase,不能defineProperty重定义属性特性
  Object.defineProperty(p1, 'name', {value:'kk', enumerable: true}); //=>error

• Object.defineProperties(object, descriptors)

  var p1 = new Person('alice');
  Object.defineProperties(p1,{
  skill:{
  value: 'singing',
  writable: true,
  enumerable: true,
  configurable: false
  },
  age: {
  value: 18,
  writable: true,
  enumerable: true,
  configurable: false
  }
  });
  p1.age //18
  p1.skill //singing

• Object.getOwnPropertyDescriptor(obj, propertyName)
  获取自有属性的descriptor

  function Person (n){ this.name = n; }
  Person.prototype = {
  constructor: Person,
  hi: function(name){ console.log('hi,'+name);}
  };
  var p1 = new Person('alice');
  var nameDescriptor = Object.getOwnPropertyDescriptor(p1, 'name');//=>{value:'alice', enumerable: true, writable: true, configurable: true}

  var des = Object.getOwnPropertyDescriptor(p1, 'hi');//=>undefined

• Object.getOwnPropertyNames(obj)
  获取对象所有的自有属性名

  //接上
  p1.age = 11;
  var props = Object.getOwnPropertyNames(p1); //=> ['name', 'age']

• Object.preventExtensions(obj)
  禁止扩展对象，即不能添加属性到对象上。

  //接上
  Object.preventExtensions(p1);
  p1.home = 'HK';
  console.log(p1.home); //=> undefined

• Object.isExtensible(obj)
  判断对象是否可扩展

  //接上
  Object.isExtensible(p1);//=> false

• Object.seal(obj) , Object.isSealed(obj)
  若对象为isSeal状态则不能添加或删除属性, 但可以修改现有属性的值

  //接上
  Object.seal(p1);
  Object.isSealed(p1); //true
  delete p1.name;//=>false
  p1.like = 'shopping';
  console.log(p1.like); //=> undefined

• Object.freeze(obj) , Object.isFrozen(obj)
  冻结对象（不能添加或删除属性，不能修改现有属性) freeze -> seal -> configurable:false 限制的严格程度递减

  Object.freeze(p1);
  Object.isFrozen(p1); //=> true
  p1.name = 'alice2';
  console.log(p1.name); //=> alice
  p1.school = 'hkzw';
  console.log(p1.school); //=> undefined

• Object.getPrototypeOf(obj);
  获取对象的原型对象

  var proto = Object.getPrototypeOf(p1);//=>{constructor: Person, hi: function(){..}}

• Array.isArray(arg)

• [].indexOf(val,[pos])

• [].lastIndexOf(val, [pos])

• [].every(fn(v, i, arr),[context])

• [].some(fn(v,i, arr), [context])

• [].forEach(fn(v, i, arr), [context])

• [].filter(fn(v, i, arr), [context])

• [].map(fn(v, i, arr), [context]);

• [].reduce(fn(prev, curr, i, arr), [primitive]);

• [].reduceRight(fn(prev, curr, i, arr), [primitive]);

• new Date().toJSON()
  序列化日期对象 输出： "2016-03-14T07:36:09.602Z"

• String.prototype.trim
  删除字符串两端空格 (" touch ").trim(); => touch