07-eng.md

'this'

The reserved key-word this is a context object, and represents the context where the code is currently being executed. Depending on where or how it is used, its value may change.

let user = {
  name: 'John',
  age: 31,
  email: '[email protected]',
  city: 'Sao Paulo',
  blogPosts: ['Chicken Potpie', '4 mashed potato recipes'],
  login: function () {
    console.log('User logged in')
  },
  logout: function () {
    console.log('User logged out')
  },
  logBlogPosts: function() {
    // the way to have access to the properties is through `this`

    this.blogPosts.forEach(post => {
      console.log(post)
    })
  }
}

user.logBlogPosts()
// Chicken Potpie
// 4 mashed potato recipes

Note that you must use function declarations for this to refer to the object in which the method is created.

this works differently within an arrow function. The value of this references the object at the point of invoking the method.

Still, there's a way of reducing the syntax for the function declaration. The alternative is removing the word function and the colon:

let user = {
  login () {
    console.log('User logged in')
  }
}