Prefer use of an object spread over Object.assign (prefer-object-spread)

The --fix option on the command line can automatically fix some of the problems reported by this rule.

When Object.assign is called using an object literal as the first argument, this rule requires using the object spread syntax instead. This rule also warns on cases where an Object.assign call is made using a single argument that is an object literal, in this case, the Object.assign call is not needed.

Rule Details

Examples of incorrect code for this rule:

Object.assign({}, foo)

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

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

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

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

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

// Object.assign with a single argument that is an object literal

Object.assign({ foo: bar });

Examples of correct code for this rule:


// Any Object.assign call without an object literal as the first argument
Object.assign(foo, { bar: baz });

Object.assign(foo, Object.assign(bar));

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

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

When Not To Use It

When you don’t care about syntactic sugar added by the object spread property.


This rule was introduced in ESLint 5.0.0-alpha.3.