Reflect.apply()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2016.

The Reflect.apply() static method calls a target function with arguments as specified.

Try it

console.log(Reflect.apply(Math.floor, undefined, [1.75]));
// Expected output: 1

console.log(
  Reflect.apply(String.fromCharCode, undefined, [104, 101, 108, 108, 111]),
);
// Expected output: "hello"

console.log(
  Reflect.apply(RegExp.prototype.exec, /ab/, ["confabulation"]).index,
);
// Expected output: 4

console.log(Reflect.apply("".charAt, "ponies", [3]));
// Expected output: "i"

Syntax

Reflect.apply(target, thisArgument, argumentsList)

Parameters

target

The target function to call.

thisArgument

The value of this provided for the call to target.

argumentsList

An array-like object specifying the arguments with which target should be called.

Return value

The result of calling the given target function with the specified this value and arguments.

Exceptions

TypeError

Thrown if target is not a function or argumentsList is not an object.

Description

Reflect.apply() provides the reflective semantic of a function call. That is, Reflect.apply(target, thisArgument, argumentsList) is semantically equivalent to:

js
Math.floor.apply(null, [1.75]);
Reflect.apply(Math.floor, null, [1.75]);

The only differences are:

Reflect.apply() takes the function to call as the target parameter instead of the this context.
Reflect.apply() throws if argumentsList is omitted instead of defaulting to calling with no parameters.

Reflect.apply() invokes the [[Call]] object internal method of target.

Examples

Using Reflect.apply()

js
Reflect.apply(Math.floor, undefined, [1.75]);
// 1;

Reflect.apply(String.fromCharCode, undefined, [104, 101, 108, 108, 111]);
// "hello"

Reflect.apply(RegExp.prototype.exec, /ab/, ["confabulation"]).index;
// 4

Reflect.apply("".charAt, "ponies", [3]);
// "i"