functionApplySpreads

Prefer the spread operator over .apply() calls.

✅ This rule is included in the ts stylistic and stylisticStrict presets.

Before ES2015, one had to use Function.prototype.apply() to call variadic functions with an array of arguments. In ES2015 and later, the spread operator (...) provides cleaner syntax for the same purpose.

This rule flags usage of .apply() when it can be replaced with spread syntax. It only reports cases where the this argument is not changed, meaning the spread replacement is safe.


const foo: (...args: unknown[]) => void
foo.
CallableFunction.apply<undefined, unknown[], void>(this: (this: undefined, ...args: unknown[]) => void, thisArg: undefined, args: unknown[]): void (+1 overload)
Calls the function with the specified object as the this value and the elements of specified array as the arguments.
@param ― thisArg The object to be used as the this object.
@param ― args An array of argument values to be passed to the function.
apply(
var undefined
undefined, 
const args: unknown[]
args);


const foo: (...args: unknown[]) => void
foo.
CallableFunction.apply<null, unknown[], void>(this: (this: null, ...args: unknown[]) => void, thisArg: null, args: unknown[]): void (+1 overload)
Calls the function with the specified object as the this value and the elements of specified array as the arguments.
@param ― thisArg The object to be used as the this object.
@param ― args An array of argument values to be passed to the function.
apply(null, 
const args: unknown[]
args);


const obj: {
    foo: (...args: unknown[]) => void;
}
obj.
foo: (...args: unknown[]) => void
foo.
CallableFunction.apply<{
    foo: (...args: unknown[]) => void;
}, unknown[], void>(this: (this: {
    foo: (...args: unknown[]) => void;
}, ...args: unknown[]) => void, thisArg: {
    foo: (...args: unknown[]) => void;
}, args: unknown[]): void (+1 overload)
Calls the function with the specified object as the this value and the elements of specified array as the arguments.
@param ― thisArg The object to be used as the this object.
@param ― args An array of argument values to be passed to the function.
apply(
const obj: {
    foo: (...args: unknown[]) => void;
}
obj, 
const args: unknown[]
args);


var Math: Math
An intrinsic object that provides basic mathematics functionality and constants.
Math.
Math.max(...values: number[]): number
Returns the larger of a set of supplied numeric expressions.
@param ― values Numeric expressions to be evaluated.
max.
CallableFunction.apply<Math, number[], number>(this: (this: Math, ...args: number[]) => number, thisArg: Math, args: number[]): number (+1 overload)
Calls the function with the specified object as the this value and the elements of specified array as the arguments.
@param ― thisArg The object to be used as the this object.
@param ― args An array of argument values to be passed to the function.
apply(
var Math: Math
An intrinsic object that provides basic mathematics functionality and constants.
Math, 
const numbers: number[]
numbers);


const foo: (...args: unknown[]) => void
foo(...
const args: unknown[]
args);


const obj: {
    foo: (...args: unknown[]) => void;
}
obj.
foo: (...args: unknown[]) => void
foo(...
const args: unknown[]
args);


var Math: Math
An intrinsic object that provides basic mathematics functionality and constants.
Math.
Math.max(...values: number[]): number
Returns the larger of a set of supplied numeric expressions.
@param ― values Numeric expressions to be evaluated.
max(...
const numbers: number[]
numbers);


const foo: (...args: unknown[]) => void
foo.
CallableFunction.apply<unknown, unknown[], void>(this: (this: unknown, ...args: unknown[]) => void, thisArg: unknown, args: unknown[]): void (+1 overload)
Calls the function with the specified object as the this value and the elements of specified array as the arguments.
@param ― thisArg The object to be used as the this object.
@param ― args An array of argument values to be passed to the function.
apply(
const otherThis: unknown
otherThis, 
const args: unknown[]
args);


const foo: (...args: unknown[]) => void
foo.
CallableFunction.apply<null, number[], void>(this: (this: null, ...args: number[]) => void, thisArg: null, args: number[]): void (+1 overload)
Calls the function with the specified object as the this value and the elements of specified array as the arguments.
@param ― thisArg The object to be used as the this object.
@param ― args An array of argument values to be passed to the function.
apply(null, [1, 2, 3]);

Options

This rule is not configurable.

When Not To Use It

This rule should not be used if you need to target ES5 or earlier JavaScript environments that don’t support the spread operator.

If you have code that intentionally uses .apply() for readability or other reasons, you may want to disable this rule.

Equivalents in Other Linters

ESLint: prefer-spread
Oxlint: eslint/prefer-spread

Made with ❤️‍🔥 around the world by the Flint team and contributors.

functionApplySpreads

Examples

Options

When Not To Use It

Further Reading

Equivalents in Other Linters