CODEWITHSUNDEEP
javascriptarraysangulartypescript
Ciprian
Ciprian

Reputation: 3226

Typescript push to specific key in array

I am working on Angular2 project using Firebase.

I need to push all query results under the same key in this.guestPush.

I have a multiple select element which contains different user levels. 4, 6, 9.

When one level is selected, the resulting object is saved in the guestPush array, but when another level is selected the following error occurs.

I get this error:

ERROR TypeError: this.guestPush[("filter" + i)].push is not a function

Here is my code : 

  guestPush: any[] = new Array;

  level.forEach((lvl, index) => {

    this.db.object(`levelsUsers/${lvl}/users`)
      .subscribe(users => {

        if (this.guestPush['filter_' + i]) {
          this.guestPush['filter_' + i].push(users);
        } else {
          this.guestPush['filter_' + i] = users;
        }

      }, err => console.log(err));

  });

Edit ***

The users object which contains the user or users which match the filter:

Object {-KmSjAaxdCUvrPEQ8InI: Object, $key: "users", $exists: function}
  -KmSjAaxdCUvrPEQ8InI: Object
    admin:"false"
    description:"desc"
    ...
    ...
    verified:false
  __proto__:Object
  exists:function ()
  $key:"users"
  __proto__:Object

And this.guestPush[i] = users; creates an object like this: 

[Object]
 0:Object
 -KmSjAaxdCUvrPEQ8InI: Object
    admin:"false"
    description:desc"
    ...
    ...
    verified:false
    __proto__:Object
  $exists:function ()
  $key:"users"
  __proto__:Object
 length:1
 __proto__:Array(0)

So in the next loop I want to add any new user objects next to -KmSjAaxdCUvrPEQ8InI or anything as long as it is added as a value of the 0 key.

Upvotes: 14

Views: 13200

Answers (5)

JGFMK
JGFMK

Reputation: 8914

Here's your problem,

guestPush: any[] = new Array;
'filter_' + i // this will yield a string.
this.guestPush['filter_' + i])

I could define an object:

let name = {};
name['x'] = 'blah';
or name.x = 'blahblah'; // name.x does same thing as name['x']

I think your thinking name['x'] = 'blah'; is an array, when it's object syntax.

Consequently you need to think about implementing a Dictionary.

Upvotes: 2

Ramesh Rajendran
Ramesh Rajendran

Reputation: 38713

@Ciprian : As per your answer.

You need a small change from your code to use. I hope this below code enough to you. 

let key ='filter_';
this.guestPush.push({ key + i : users });

Upvotes: 2

Vamshi
Vamshi

Reputation: 9351

Looks like you are getting an array response and you are assigning it to the object : 

this.guestPush['filter_' + i] = users;

so this.guestPush['filter_'+ i] is of type array now. If you want to add another users object to it , you are essentially adding another array to existing array. In that case shouldn't you be using concat ? 

if (this.guestPush['filter_' + i]) {
    this.guestPush['filter_' + i].concat(users);
} else {
    this.guestPush['filter_' + i] = users;
}

if users is not an array, then it should be 

if (this.guestPush['filter_' + i]) {
    this.guestPush['filter_' + i].push(users);
} else {
    this.guestPush['filter_' + i] = [users];
}

Upvotes: 11

Ciprian
Ciprian

Reputation: 3226

I ended up using

 this.guestPush.push({ [i]: { [key]: obj } });

Upvotes: 9

basarat
basarat

Reputation: 276343

Typescript push to specific key in array

You need to use the splice method on the array : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice

Upvotes: 1

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