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Create an object with dynamic keys

Written byPhuoc Nguyen
Created
25 Feb, 2021
Category
Tip
Tags
JavaScript
We often use the bracket notation to add a dynamic key to an object.
js
const key = 'ages';
const person = {
name: 'John Doe',
};

person[key] = 42;
ES6 allows us to do that in a declarative way as following:
js
const key = 'ages';
const person = {
name: 'John Doe',
[key]: 42,
};
Here is a simple usage. The sample code below returns the list of name and value of given input fields in a form:
js
// `formEle` is the form element
const data = [...formEle.querySelectorAll('input')].map((field) => {
return {
[field.getAttribute('name')]: field.getAttribute('value'),
};
});
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Phước Nguyễn