Hello, I have a question about this code snippet. Can you please explain why it is returning a function instead of the x value? Thank you in advance.
function f() {
function createClosure(x) {
return function(){
return x;
};
}
var arr = [];
var index;
for(index = 0; index < 3; index++) {
arr[index] = createClosure(index);
}
return arr;
}
var result = f();
console.log(result[0]);
createClosure is a function that generates other functions, resulting in an array b filled with these generated functions.
Calling b[0] will retrieve the function itself, while invoking b[0]() will return the result of x.
Upon examining the function makeClosure, it is evident that it produces a function which, when called, yields the value of x.
Inside the loop, the statement a[i] = makeClosure(i); stores the function generated by makeClosure(i) at the specified index i within the array.
By executing a function stored at a specific index in the array, you can retrieve the corresponding value of x.
Therefore, calling a[0](); is expected to result in 0.
When you call the function f(), it will give you back an array.
By doing var a=f(), you are storing that array in variable a.
Each element inside the array is actually a function. So if you try to access any element in the array a, you will only get the function definition and it won't run automatically.
To execute the function, you must treat the elements in the array as functions. For example, instead of just calling a[0] like this console.log(a[0]);, you should call it like this: console.log(a[0]());
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