1 answers

0 points

Asked by:

435

How can I create object property from variable value?

I want to add a new property to myObject, name it key1 and give it a value of value1 but when I do this it returns undefined:

xxxxxxxxxx
 
var myObject = new Object();
​
var key = 'key1';
var value = 'value1';
​
myObject.key = value;
​
console.log(myObject.key1); // returns 'undefined'
console.log(myObject.key);  // returns 'value1'

Auto running

1 answer

0 points

Answered by:

Admin Dirask Community

4380

There are two types of property accessors in JavaScript: dot notation and bracket notation.

Use bracket notation to create object property from the variable value:

xxxxxxxxxx
 
myObject[key] = value;

Practical example

xxxxxxxxxx
 
var myObject = {};
​
var key = 'key1';
var value = 'value1';
​
myObject[key] = value;
​
console.log(myObject.key1);    // value1
console.log(myObject['key1']); // value1

Auto running

Alternative solution (ES6+)

xxxxxxxxxx
 
const key = 'key1';
const value = 'value1';
​
let myObject = {
    [key]: value,
};
​
console.log(myObject.key1);    // value1
console.log(myObject['key1']); // value1