For 循环在数组中不起作用（Javascript，Angular 2）

Question

I have an array that contains cameras specifications, the problem occurs when I try to run a for loop to get the elements.

Here is the content of my array :

I tried all different types of for loops like forEach, basic for loop with increment or for ( let item of myArray )

For loop doesn't run and I have no return of the element in the array.

for (let id in elements) {

      if (typeof elements[id].brands !== 'undefined') {

        delete this.items;

        let itemsArray = [];

        for (let elementData of elements[id].brands) {

          this.http.get("assets/data/" + elementData + "Reflex.json").map(res => res.json()).subscribe(data => {

            Array.prototype.push.apply(itemsArray, data);

          });

        }

        this.items = itemsArray;

      }

      if (typeof elements[id].sensorSize !== 'undefined') {


      }

    }

( this.items is the array that you can see on the top (I use Angular2)).

Answer 1

Try this code, it will iterate on the array itself and return all items in it as objects in the inline function.

this.items.forEach( function (item)
{
 item.xxx=11;
} );

Answer 2

  this.http.get("assets/data/" + elementData + "Reflex.json").map(res => res.json()).subscribe(data => {

    Array.prototype.push.apply(itemsArray, data);

  });

This call is the problem.It is asynchronous .

The for loop will not wait for the response to push data into itemArray . A rough way to get the array is:

      this.http.get("assets/data/" + elementData + "Reflex.json").map(res => res.json()).subscribe(data => {

        Array.prototype.push.apply(this.items, data);//make sure this.items is set to empty previous to call

      });