Declaring array of objects

Question

I have a variable which is an array and I want every element of the array to act as an object by default. To achieve this, I can do something like this in my code.

Answer 1

The below code from my project maybe it good for you

  reCalculateDetailSummary(updateMode: boolean) {

    var summaryList: any = [];
    var list: any;
    if (updateMode) { list = this.state.pageParams.data.chargeDefinitionList }
    else {
        list = this.state.chargeDefinitionList;
    }

    list.forEach((item: any) => {
        if (summaryList == null || summaryList.length == 0) {
            var obj = {
                chargeClassification: item.classfication,
                totalChargeAmount: item.chargeAmount
            };
            summaryList.push(obj);

        } else {
            if (summaryList.find((x: any) => x.chargeClassification == item.classfication)) {
                summaryList.find((x: any) => x.chargeClassification == item.classfication)
                    .totalChargeAmount += item.chargeAmount;
            }
        }
    });

    if (summaryList != null && summaryList.length != 0) {
        summaryList.push({
            chargeClassification: 'Total',
            totalChargeAmount: summaryList.reduce((a: any, b: any) => a + b).totalChargeAmount
        })
    }

    this.setState({ detailSummaryList: summaryList });
}

Answer 2

Using forEach we can store data in case we have already data we want to do some business login on data.

var sample = new Array();
var x = 10;
var sample = [1,2,3,4,5,6,7,8,9];
var data = [];

sample.forEach(function(item){
    data.push(item);
})

document.write(data);

Example by using simple for loop

var data = [];
for(var i = 0 ; i < 10 ; i++){
   data.push(i);
}
document.write(data);

Answer 3

Try this-

var arr = [];
arr.push({});

Answer 4

You can instantiate an array of "object type" in one line like this (just replace new Object() with your object):

var elements = 1000;
var MyArray = Array.apply(null, Array(elements)).map(function () { return new Object(); });

Answer 5

Use array.push() to add an item to the end of the array.

var sample = new Array();
sample.push(new Object());

you can use it

var x = 100;
var sample = [];
for(let i=0; i<x ;i++){
  sample.push({}) 
  OR
  sample.push(new Object())
}    

Answer 6

If you want all elements inside an array to be objects, you can use of JavaScript Proxy to apply a validation on objects before you insert them in an array. It's quite simple,

const arr = new Proxy(new Array(), {
  set(target, key, value) {
    if ((value !== null && typeof value === 'object') || key === 'length') {
      return Reflect.set(...arguments);
    } else {
      throw new Error('Only objects are allowed');
    }
  }
});

Now if you try to do something like this:

arr[0] = 'Hello World'; // Error

It will throw an error. However if you insert an object, it will be allowed:

arr[0] = {}; // Allowed

For more details on Proxies please refer to this link: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy

If you are looking for a polyfill implementation you can checkout this link: https://github.com/GoogleChrome/proxy-polyfill