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<script>
var test=(function(a){
this.a=a;
return function(b){
return this.a+b;
}
}(function(a,b){
return a;
debugger;
}(1,2)));
console.log(test(4))
//结果是输出5 求解?
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女神的闺蜜爱上我2017-07-07 10:36:36
Memory
let functionA = function (a) {
this.a = a
return function (b) {
return this.a + b
}
}
let argA = function (a, b) {
return a
debugger
}(1, 2)
// 实际上 argA 就等于 1，** 这个地方的 b 没有被用到 **The original formula is simplified to:
let test = functionA(argA)After this sentence is executed, test is actually
function (b) {
return this.a + b
}
// ** 这是一个带一个参数的函数，执行 test(4) 时 b 就是 4 **And at this time this.a is equal to 1. Therefore the result of test(4) is 5
黄舟2017-07-07 10:36:36
Obviously it’s 5
var test = function(a){
this.a = a;
return function(b){
return this.a + b;
}
}(function(a,b){
return a;
}(1,2))Breakdown
var test = function(a){
this.a = a;
return function(b){
return this.a + b;
}
}
var getA = function(a,b){
return a;
}
test(getA(1,2))(4);If you still don’t understand this, you have to learn the basics
typecho2017-07-07 10:36:36
First we need to understand the variable test. Test is actually a function, as follows
var test = function(b){
return this.a + b;
}The outer part is a function that is executed immediately. First,
function(a,b){
return a;
}(1,2)The result of this part is 1, that is to say, the code can be simplified to:
var test=(function(a){
this.a=a;
return function(b){
return this.a+b;
}
}(1));
In the above code, a=1, therefore, in test(4), we get:
var test=(function(a){ // a = 1
this.a=a;
return function(b){ // b = 4
return this.a+b; // 得到 1 + 4
}
}(1));