functionvarInLoopExample(){varfuncs=[];for(vari=0;i<3;i++){funcs.push(function(){console.log(i);});}funcs[0]();// 输出: 3funcs[1]();// 输出: 3funcs[2]();// 输出: 3// 因为循环结束后 i 的值是 3,所有函数都引用了同一个 i 变量}varInLoopExample(); 1. 2. 3. 4. 5...
According to Stack Overflow Developer Survey 2023, JavaScript is the most commonly used language for the 11th year straight, with 54.45% of people opting for it. The major reason for its popularity is that JavaScript is versatile and can be used for both front-end and back-end development and...
}//遍历目标数据for(let iintarget) {//获取遍历数据结构的每一项值。let value =target[i]//判断目标结构里的每一值是否存在对象/数组if(checkedType(value) === 'Object' || checkedType(value) === 'Array') {//对象/数组里嵌套了对象/数组//继续遍历获取到value值result[i] =clone(value) }else{...
for...of 语句执行一个循环,该循环处理来自可迭代对象的值序列。可迭代对象包括内置对象的实例,例如 Array、String、TypedArray、Map、Set、NodeList(以及其他 DOM 集合),还包括 arguments 对象、由生成器函数生成的生成器,以及用户定义的可迭代对象。
eslint: no-var jscs: disallowVar 因为let是块级作用域,而var是函数级作用域 // bad var count = 1; if (true) { count += 1; } // good, use the let. let count = 1; if (true) { count += 1; }2.3 注意: let、const都是块级作用域 // const and let only exist in the blocks...
// badvarcount =1;if(true) { count +=1; }// good, use the let.letcount =1;if(true) { count +=1; } 2.3注意,let 和 const 都是块级范围的。 // const 和 let 只存在于他们定义的块中。{leta =1;constb =1; }console.log(a);// ReferenceErrorconsole.log(b);// ReferenceError ...
let is only visible in the for() loop and var is visible to the whole function.function allyIlliterate() { //tuce is *not* visible out here for( let tuce = 0; tuce < 5; tuce++ ) { //tuce is only visible in here (and in the for() parentheses) //and there is a ...
The let, var, and const have similar syntax for variable declaration and initialization, but they differ in their scope and usage.
13.2 Use one const or let declaration per variable. eslint: one-var Why? It’s easier to add new variable declarations this way, and you never have to worry about swapping out a ; for a , or introducing punctuation-only diffs. You can also step through each declaration with the ...
In that case, you can choose between two different loops, a do loop and a while loop. Both of them are pretty similar and you’ll be choosing based on your personal preference. Let’s show you how they work.For example, if you want to keep questioning the user until he gets the ...