Push int to String array

Question

I am using an autocomplete and I want to store the ID´s of the chosen users.

I want to store the IDs in an array of strings, and this array must only have unique values (cannot have duplicate values)

I tried to push and convert values (using tostring ()) but to no avail.

Can anyone get me some help?

The desired output (example): ["1", "2", "3", "4"]

My code DEMO

COMPONENT

 ngOnInit() {
    this.userService.getUsers().subscribe(
      (val: any[]) =>{
        this.allFruits = val.map(user => {
      this.nameIdMap.set(user.username, user.id);
      return user.username
    });
        this.fruitCtrl.setValue(null); //use this to apply changes instantly
      } 
    )
  }

  remove(fruit: string): void {
    const index = this.fruits.indexOf(fruit);

    if (index >= 0) {
      this.fruits.splice(index, 1);
    }
  }

arr:any;
selected(event: MatAutocompleteSelectedEvent): void {
  var a = this.nameIdMap.get(event.option.viewValue);
  console.log(a);
  // var b = this.arr.push(a);
  // var c = b.map((input) => input).join(",").toString();
  // console.log(c)
  this.fruits.push(event.option.viewValue);
  this.fruitInput.nativeElement.value = '';
  this.fruitCtrl.setValue(null);
}

"and this array must only have unique values" developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… — Matt
– Matt, Commented Jan 9, 2020 at 19:58

Alexis Tamariz · Accepted Answer · 2020-01-09 21:10:46Z

3

will be like this.

selected(event: MatAutocompleteSelectedEvent): void {
  var a = this.nameIdMap.get(event.option.viewValue);
  //this makes sure selected id does not exist
  if( this.arr.filter(x => /*makes cast int to string to compare items*/ String(a) == x).length < 1) {
      this.arr.push(String(a));
      this.fruits.push(event.option.viewValue);
  }
  console.log(a, this.arr);

  this.fruitInput.nativeElement.value = '';
  this.fruitCtrl.setValue(null);
}

make you sure arr variable is initialized since you declare it.

arr:any[] = [];

hope it be by helpful. D;

answered Jan 9, 2020 at 21:10

Alexis Tamariz

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Comments

StriplingWarrior · Accepted Answer · 2020-01-09 20:27:47Z

2

Your array is declared, but never initialized. First you need to initialize it. And since you want it to be a string array you should declare it as such:

arr:string[] = [];

Then you need to convert your numbers to strings if you want to push them into that array. The push method doesn't return the array, so you have to keep referring to the field itself rather than capturing the result the way you're trying to do.

  this.arr.push(a.toString());
  var c = this.arr.map((input) => input).join(",").toString();
  console.log(c)

edited Jan 9, 2020 at 20:27

answered Jan 9, 2020 at 20:18

StriplingWarrior

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2 Comments

Paul sk Over a year ago

Thank you for your help ! I think your link is the same as the post. Push already works, now how do I pass this information to an array of strings?

StriplingWarrior Over a year ago

I removed the link, since it's not necessary. Clarify your question: you don't "pass information" to an array.

Matt · Accepted Answer · 2020-01-09 20:02:09Z

0

let a = new Set();
a.add(String(1));
console.log(Array.from(a)); // ["1"]

answered Jan 9, 2020 at 20:02

Matt

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2 Comments

Matt Over a year ago

Can you break it down to the minimal code example to illustrate the problem?

Paul sk Over a year ago

I have this in my demo, I can only get the ID´S correctly ... the rest of the code is commented because it is not working :(

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