JavaScript - convert array to object with values as keys

In this article, we would like to show you how to convert array to object with array values as keys working with JavaScript.

Quick solution:

// ONLINE-RUNNER:browser;

const array = ['a', 'b', 'c'];
const object = array.reduce((object, item) => (object[item] = item, object), {});

console.log(JSON.stringify(object, null, 4));

or: 

// ONLINE-RUNNER:browser;

const array = ['a', 'b', 'c'];
const result = array.reduce((object, item) => ({...object, [item]: item}), {});

console.log(JSON.stringify(result, null, 4));

Warning: the solution based on spread operator is not recommended because of bad time performance.

Practical examples

In this examples, we create a reusable function that converts the array to object with the array values as keys using reduce() method.

1. Assigning property based example

// ONLINE-RUNNER:browser;

const toObject = (array) => {
    return array.reduce((object, item) => (object[item] = item, object), {});
};


// Usage example:

const array = ['a', 'b', 'c'];
const object = toObject(array); 

console.log(JSON.stringify(object, null, 4));

2. Spread operator based example

// ONLINE-RUNNER:browser;

const toObject = (array) => {
    return array.reduce((object, item) => ({ ...object, [item]: item }), {});
};


// Usage example:

const array = ['a', 'b', 'c'];
const object = toObject(array); 

console.log(JSON.stringify(object, null, 4));

Warning: the solution based on spread operator is not recommended because of bad time performance.

See also

1. JavaScript - convert array to object

References

1. Spread syntax (...) - JavaScript | MDN