在 Z686155AF75A60A0F6E9D80C1F7EDDE3 中的 Map object 中访问对象和 arrays

Question

I am simulating a database with the Map object and storing data where the key is an UserId and the value is an object containing fields that also can be an object or an array. When I need to, for example, push new data to the array inside there, what would be the best course of action if any at all? As per now the Map key/value elements are in this format:

   'someUserID', // Key

     // Value as object under here:

     {
       id: 'Marty',  
       password: // A hashed password as a String,
       friends: [Array],
       posts: [Array]
     }

If I want to push new elements to the posts field do I have to do an Arrayfrom the whole key/value pair, do the push to where I need and then use.set to bring the modification back inside the Map object? Is there any clever way to do this?

Thanks in advance, (Yes. I'm quite the beginner when it comes to this..: :) )

Answer 1

I see you mention "Map", as in the ES6 Map object. I don't see why you need to use Map, a simple JS object should suffice.

Here's an example of manipulating arrays in a simple JS object,

 const db = { userId: { id: 'Marty', posts: ['My first post,'], }; }. db['userId'].posts;push('My second post.'); console.log(db);

Similarly, here's an example of manipulating objects in a simple JS object,

 const db = { userId: { id: 'Marty', contact: { email: 'martymcfly@gmail.com', }, }, }; db['userId'].contact.phoneNumber = '8527107655'; console.log(db);

If you insist on using ES6 Map then here is the same example for that,

let db = new Map();

db.set('userId', {
  id: 'Marty',
  posts: ['My first post!'],
  contact: {
    email: 'martymcfly@gmail.com',
  },
});

db.get('userId').posts.push('My second post!');

db.get('userId').contact.phoneNumber = '8527107655';

console.log(db);

Answer 2

const db = { 
             userId: { id: 'Marty',  
                     password: password
                     friends: [Array],
                     posts: [Array]
                    },

             }


   const values = db[userId]
    values.posts.push("new post")

You can get the value using the userId key and the value returned can be pushed just like a normal array