How to create multiple objects at once and push inside an array

Question

I wanted objects like this:

  [{ age: 3, area: 5 }, 
   { age: 4, area: 15 }, 
   { age: 19, area: 3 }, 
   { age: 16, area: 11 }, 
   { age: 20, area: 4 }, 
   { age: 6, area: 9 }]

The approach was to create new objects each time and push it inside an array.

  function Numstuff(age,area) {
      this.age = age,
      this.area = area
  }

  var numObjArray = []

var createObj = new Numstuff (Math.floor(Math.random() * 20), 
Math.floor(Math.random() * 20))



numObjArray.push(createObj)

But This pushes only one. How to create multiple objects and push inside an array?

If you're sure you're never going to use the NumStuff constructor without wanting the new object added to the array, you can put numObjArray.push(this) at the end of the constructor. — Robin Zigmond
– Robin Zigmond, Commented Oct 30, 2018 at 19:51
Or, if all values will be generated the same way, just use a loop — Robin Zigmond
– Robin Zigmond, Commented Oct 30, 2018 at 19:52

Mark · Accepted Answer · 2018-10-30 19:49:35Z

1

You can make an array directly with Array.from() and fill it with your objects by passing a function:

function Numstuff(age,area) {
    this.age = age,
    this.area = area
}

// make 10 numstuffs
const num = 10
let arr = Array.from({length: num}, () => new Numstuff (Math.floor(Math.random() * 20), Math.floor(Math.random() * 20)))

console.log(arr)

answered Oct 30, 2018 at 19:49

Mark

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Ved · Accepted Answer · 2018-10-30 20:08:16Z

1

What about this:

var array = [];
var obj = {};

for(var i=0;i<=10;i++){
  
  obj = {age: i, area: Math.random()}
  array.push(obj);
}

console.log(array)

edited Oct 30, 2018 at 20:08

answered Oct 30, 2018 at 19:49

Ved

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3 Comments

Mark Over a year ago

Why are you creating all the extra empty objects?

Ved Over a year ago

@MarkMeyer are you talking about obj ?

Mark Over a year ago

Yes, let obj = {age: i, area: Math.random()} in the loop is enough. You don't need the other obj = {}

Ariel · Accepted Answer · 2018-10-30 19:50:26Z

0

Maybe with a for loop. Using you own code:

for (var i = 0; i < 9; i++) {
    var createObj = new Numstuff (Math.floor(Math.random() * 20), 
    Math.floor(Math.random() * 20))
    numObjArray.push(createObj)
}

answered Oct 30, 2018 at 19:50

Ariel

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