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apply() in JavaScript

By: Yolander in Javascript Tutorials on 2023年04月26日 [フレーム]

apply() is a method in JavaScript that allows you to call a function with a given this value and arguments provided as an array. It is similar to the call() method, but with apply(), the arguments are passed as an array, while with call(), the arguments are passed individually.

The syntax for the apply() method is as follows:

function.apply(thisArg, [argsArray])

Here, thisArg is the value of this that you want to use when calling the function, and argsArray is an array-like object containing the arguments to pass to the function.

Here's an example of how to use apply() to call a function with a given this value and arguments:

function sayHello(greeting) {
 console.log(greeting + ', ' + this.name + '!');
}
var person = {
 name: 'John'
};
sayHello.apply(person, ['Hello']); // prints "Hello, John!"

In this example, apply() is used to call the sayHello() function with the person object as the this value and the string 'Hello' as the argument.

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