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How to use methods and this

Updated September 2026 · Beginner-friendly guide

Add a method

A method is a function stored on an object. In a normal method call, this refers to the object before the dot.

const counter = {
  value: 0,
  increment() {
    this.value += 1;
    return this.value;
  }
};
console.log(counter.increment());

Understand the call site

Extracting a method loses its receiver, so this is no longer the original object. Modules and strict mode make such mistakes easier to notice.

"use strict";
const user = {
  name: "Nia",
  introduce() { return `I am ${this.name}`; }
};
console.log(user.introduce());
// const speak = user.introduce;
// speak(); // this is undefined

Bind a receiver when needed

bind creates a function whose this is fixed. This is useful when passing a method as a callback.

const timer = {
  label: "Study",
  show() { console.log(this.label); }
};
const showTimer = timer.show.bind(timer);
showTimer();

Know arrow function behavior

Arrows capture this from their surrounding scope, so they are usually unsuitable as object methods that need the receiver.

const team = {
  name: "Blue",
  members: ["Ana", "Bo"],
  labels() {
    return this.members.map(member => `${this.name}: ${member}`);
  }
};
console.log(team.labels());

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