CODEWITHSUNDEEP
javascript
cristodagama
cristodagama

Reputation: 57

How could I iterate with a for loop to create many objects with Object.create on the fly in javascript?

I am trying to create a function that will dynamically create objects on the fly based on the input number arguments, but I'm running into an issue with iterating over the Object.create() part. I don't know where to play my i in the for loop, but ideally I would have all the sportsCar objects stored in the sportArray. That is the target at least.

function car(doors, capacity, storage) {
  this.doors = doors;
  this.capacity = capacity;
  this.storage = storage;
};


var van = Object.create(car);
van.doors = 4;
van.storage = "rear storage";

var miniVan = Object.create(van);
miniVan.capacity = "200 LB";

var cargoVan = Object.create(van);
cargoVan.capacity = "800 LB";

var truck = Object.create(car);
truck.doors = 2;
truck.storage = "bed";
truck.capacity = "1500 LB";

var familyCar = Object.create(car);
familyCar.doors = 4;
familyCar.storage = "large trunk";
familyCar.capacity = "300 LB";

var sportsCar = Object.create(car);
sportsCar.doors = 2;
sportsCar.storage = "small trunk";
sportsCar.capacity = '100 LB'; 

function tally(n1, n2, n3, n4, n5) {
      var sportArray = [];
      var familyArray = [];
      var truckArray = [];
      var miniArray = [];
      var cargoArray = [];

    sportsObjs = for(var i = 0; i < n1; i++){
       Object.create(sportsCar);
    }

    sportArray.push(sportsObjs);

    for (var i = 0; i < n2; i++){
       Object.create(familyCar);
    }

    for(var i = 0; i < n3; i++){
       Object.create(truck)
    }

    for(var i = 0; i < n4; i++){
        Object.create(miniVan)
    }

    for(var i = 0; i < n5; i++){
        Object.create(cargoVan)
    }

    return console.log(sportsArray);

}

Upvotes: 0

Views: 67

Answers (2)

Davide Lorenzo MARINO
Davide Lorenzo MARINO

Reputation: 26926

You need only to push objects in the array inside the loop:

 function tally(n1, n2, n3, n4, n5) {
    var sportArray = [];
    var familyArray = [];
    var truckArray = [];
    var miniArray = [];
    var cargoArray = [];

    for(var i = 0; i < n1; i++){
        sportArray.push(Object.create(sportsCar));   // To create a generic Object   sportArray.push({});
    }

    ....  // And so on for all the arrays
}

The problem is that you declared the different arrays as var so they are not visible outside the body of the function.

You need to return an object containg all the arrays, something like that:

function tally(n1, n2, n3, n4, n5) {
    var sportArray = [];
    var familyArray = [];
    var truckArray = [];
    var miniArray = [];
    var cargoArray = [];

    ...

    return {
        sportArray: sportArray,
        familyArray : familyArray,
        truckArray: truckArray,
        miniArray: miniArray,
        cargoArray: cargoArray
    }
}

So you can do something like:

var result = tally(3, 4, 5, 6, 7);
console.log(result.sportArray.length);

To be more succint with parameters:

function tally(parameters) { ... for (var i = 0; i < parameters.n1; i++) { ... } ... }

Calling tally in this manner:

var result = tally({n1: 3, n2:4, n3:5, n4:6, n5:7});

Upvotes: 0

Bergi
Bergi

Reputation: 664385

sportsObjs = for(var i = 0; i < n1; i++){
   Object.create(sportsCar);
}

sportArray.push(sportsObjs);

That's a plain syntax error. A loop is a statement in JavaScript, not an expression - it doesn't yield a value. You can't assign it to a variable. What you actually want is to assign each newly created object to the variable, and then push that particular new object to the array:

for (var i = 0; i < n1; i++){
    var sportsObj = Object.create(sportsCar);
    sportArray.push(sportsObj);
}

Upvotes: 1

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