for of 不能循环普通的对象,需要通过Object.keys搭配使用。 对于他们的区别,一般就看下面一段代码就可: 1 {<br> const b = [1, 2, 3, 4];// 创建一个数组<br> b.name = '小明'; // 给数组添加一个属性<br> Array.prototype.age = 12; // 给数组的原型也添加一个属性<br> console
for in (遍历所有可枚举属性,不仅是 own properties 也包括原型链上的所有属性) Object.keys(只返回对象本身具有的可枚举的属性) JSON.stringify() (只读取对象本身可枚举属性,并序列化为JSON字符串) Object.assign() (复制自身可枚举的属性,进行浅拷贝) 引入enumerable的最初目的,就是让某些属性可以规避掉for.....
[]:{}Object.keys(obj).forEach(key=>{constvalue=obj[key]// 如果深层依然是对象 递归调用constcloneValue=isReferenceType(value)?cloneDeep(value):value cloneObj[key]=cloneValue})returncloneObj}constobject1={name:'19Qingfeng',yellow:false,release:{custom:true,github:'19Qingfeng'}}constcloneValue=...
适用于循环次数未知,或者计算循环次数比较麻烦情况下;或者只是进行集合或数组遍历; 无法中途跳出forEach循环,break命令或return命令都不能生效。 不能对数组或集合进行修改(添加删除操作),如果想要修改就要用for循环。 3.Object.keys(): 返回对象自身可枚举属性组成的数组 不会遍历对象原型链上的属性以及 Symbol 属性 ...
> <video loop="true" ...> <video controls="false" ...> Note: The example with controls="false" can be a point of confusion for new developers - it will actually turn controls on! These are correct: <video controls ...> <video loop="loop" ...> <video ...> Player Readiness ...
loop Type:boolean Causes the video to start over as soon as it ends. muted Type:boolean Will silence any audio by default. poster Type:string A URL to an image that displays before the video begins playing. This is often a frame of the video or a custom title screen. As soon as the...
keys(state).filter( agentId => state[agentId].keyBelief ).length const numberBeliefsFalse = Object.keys(state).filter( agentId => !state[agentId].keyBelief ).length console.log(`True: ${numberBeliefsTrue}; False: ${numberBeliefsFalse}`) return agents }...
(); });/** *@api{patch} / Patch a user * ... */router.patch('/:id', userEditMiddleware, userValidator,async(ctx) => {if(!Object.keys(ctx.form).length) {returnctx.error(400, {message:'Nothing to update.'}); }awaitctx.user.update(ctx.form); ctx.body= ctx.user.toJSON()...
var i, // The loop counter. k, // The member key. v, // The member value. length, mind = gap, partial, value = holder[key]; // If the value has a toJSON method, call it to obtain a replacement value. if (value && typeof value === 'object' && ...
508 "loop detected" 510 "not extended" 511 "network authentication required" 注意: 不用太在意记住这些字符串, 如果你写错了,可以查阅这个列表随时更正. 由于response.status默认设置为404,因此发送没有 body 且状态不同的响应的操作如下: ctx.response.status = 200; // 或其他任何状态 ctx.response.status...