javascript push key value into object with index

November 28, 2021

I have a object variable and i want to push into my object a new { key: "value" } but with a loop and using loop index.

Something like this:

    let headers = {
        product_title: "Product Name",
        action: "Status",
        quantity: "Quantity",
        priority: "Priority",
    };

    for (let i = 0; i < bigger; i++) {
        headers = { ...headers, ...{ 'org_{i}': i } };
    }

is there a way to do something like this or add unique key with indexes?

Finally i need something like below:

let headers = {
   ...old data
   key_1: "",
   key_2: "",
   key_3: "",
};

>Solution :

There’s an ES6 thing called "computed properties" which allow regular JS enclosed in [] to form a string key…

let headers = {
  product_title: "Product Name",
  action: "Status",
  quantity: "Quantity",
  priority: "Priority",
};

for (let i = 0; i < 5; i++) {
  headers = { ...headers, ['key_' + i]: i }
}

console.log(headers)

Neat, but this creates a throw-away object for each iteration. Skipping the literal with the spread, you can use older JS, more efficiently…

let headers = {
  product_title: "Product Name",
  action: "Status",
  quantity: "Quantity",
  priority: "Priority",
};

for (let i = 0; i < 5; i++) {
  headers['key_' + i] = i
}

console.log(headers)