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ricardo leiva sikic
Asked: 2020-06-05 08:39:57 +0800 CST 2020-06-05 08:39:57 +0800 CST

attribute of an object using this [duplicate]

  • 772

Hi I am creating a simple object in js by which it has id, and slug. The grace is that through this I can access the id of this, when I request the output of the object it gives me an undefined value.

    const post = {
      id: 1,
      slug: `post-${this.id}`
    }

    console.log(post);

javascript

2 Answers

  1. Best Answer

    You need a function to change the context and with it the value of thisso you can use the id:

    const arrayDePost = [];
let post = {
    id: 1,
    slug: function() { return `post-${this.id}` },
};

arrayDePost.push(post);

post = {
    id: 2,
    slug: function() { return `post-${this.id}` },
};

arrayDePost.push(post);

console.log(arrayDePost[0].slug());
console.log(arrayDePost[1].slug());

    An anonymous function can give erroneous results by not changing the context, you would not be using the object's value.

    • 3

  2. You can put it inside an anonymous method and in this way encapsulate the value and the result, the detail is that you would access it as a method

    const post = {
  id: 1,
  slug: () => `post-${post.id}`
}

console.log(post.slug());
post.id = 5;
console.log(post.slug());

    • 1