Prefer using an object spread over `Object.assign`

Docs > Code Analysis > Static Analysis Rules > Prefer using an object spread over `Object.assign`

Metadata

ID: javascript-best-practices/prefer-object-spread

Language: JavaScript

Severity: Warning

Category: Performance

Description

This rule encourages the use of the object spread syntax over the Object.assign method when creating a new object from an existing one where the first argument is an empty object. This is because the object spread syntax is more concise, easier to read, and can eliminate the need for null checks that are often necessary with Object.assign.

If you need to use Object.assign, make sure that the first argument is not an object literal, as this can easily be replaced with the spread syntax.

Non-Compliant Code Examples

Object.assign({}, foo);

Object.assign({}, {foo: 'bar'});

Object.assign({ foo: 'bar'}, baz);

Object.assign({}, baz, { foo: 'bar' });

Object.assign({}, { ...baz });

Object.assign({});

Object.assign({ foo: bar });

Compliant Code Examples

({ ...foo });

({ ...baz, foo: 'bar' });

Object.assign(foo, { bar: baz });

Object.assign(foo, bar);

Object.assign(foo, { bar, baz });

Object.assign(foo, { ...baz });