javascript - for loop i problem

Question

There is an array outside the for loop and an object inside the for loop. Each for loop makes an attribute value of the object equal to the corresponding i item of the array and then pushes the object into the empty array. Why is the empty array displayed later? It's exactly the same. Even if I wrap the for with a word execution function, it doesn't work either

Answer 1

When you say that the last part of the new array is the same, do you mean that the elements in the array are all the same? It should be a scope issue, which should be solved by using closures.

Answer 2

When you push the object in the loop body into the empty array, do you do it inside the loop body or after it ends? Isn’t the content in the empty array you mentioned this object?

Answer 3

let obj={a:1};
let arr = [{a:1},{a:2},{a:3},{a:1,b:1}];
let arr2 =[];
for(let o of arr){
    if(o.a == obj.a){
        arr2.push(o);
    }
}
console.log(arr2);//arr2=[{a:1},{a:1,b:1}]

I guess the function described by the poster should be like this. There is no closure problem. Can the author post the code?

Answer 4

I have also encountered this type of problem before. After pushing the items looped from a collection into an array, I finally found that the items in the array are all the same. The reason is not very clear. The solution is to first push the items looped into item copy, and then push the value obtained by this copy into the array;

//此处只是随意举个例子
var a=[1,2,3,4,5,6];
var b=[];
for(let o of a)
{
    b.push(o.clone());
}

Answer 5

talk is cheap，show me the code

Answer 6

did not send the code , is to brush rogue