Pasting array of JSON into typescript array

Question

I have an array of JSON and want to paste it into an array variable in typescript.

the JSON I receive from http://www.example.com/select.php:

{ 
     "User":[ 
      {"Name":"Luca M","ID":"1"},
      {"Name":"Tim S","ID":"2"},
      {"Name":"Lucas W","ID":"3"} 
     ] 
    }

I would like to get an array like that:

  this.items = [
          'Luca M',
          'Tim S',
          'Lucas W'
        ];

EDIT:

current code is

 this.http.post('http://www.example.com/select.php', creds, {
          headers: headers
      })
          .map(res => res.json().User) 

          .subscribe(
          data => this.data = data.User.map(user => user.Name), 
          err => this.logError(err),
          () => console.log('Completed')
          );


      this.items = this.data;

error:

Cannot read property 'map' of undefined

how can I realize this?

Thanks and best regards

Nitzan Tomer · Accepted Answer · 2017-04-25 20:58:59Z

2

For this very specific json:

const json = {
    "User": [
        { "Name": "Luca M", "ID": "1" },
        { "Name": "Tim S", "ID": "2" },
        { "Name": "Lucas W", "ID": "3" } 
    ] 
}

const items = json.User.map(user => user.Name);
console.log(items); // ["Luca M", "Tim S", "Lucas W"]

(code in playground)

answered Apr 25, 2017 at 20:58

Nitzan Tomer

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7 Comments

dzitrus Over a year ago

Thanks for your suggestion, I forgot to mention, that I receive my JSON from an API. Could you help me once more according to my Edit?

dzitrus Over a year ago

I tried const json = JSON.stringify(this.data); this.items = this.data.map(user => user.Name); but this did not work as I expected

Nitzan Tomer Over a year ago

You don't need to stringify your data, if you do that you end up with a string and not an object...

dzitrus Over a year ago

Alright, makes sense, but it does not work either this.items = this.data.map(User => User.Name); --Cannot read property 'map' of undefined

Nitzan Tomer Over a year ago

You're probably doing an asynchronous operation. You need to wait until that is finished. Do that part in the subscribe callback: data => this.data = data.User.map(user => user.Name)

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