The best way to merge two arrays in one array and filter this

ionic ionic-v3
#1

I need a suggestion to merge two arrays that get data from promise and filter this merged array.

I try but i have a trouble with async data.

public sponsored_items: any = [];

constructor() {
this.get_structures();
this.get_banners();
this.arrayFilter();
}

  get_structures() {
    this.getStrucutres.get_structures(1)
      .then(data => {
        console.log(data);
        this.partners = data.results
        this.arraypartners = this.partners

        for (var i = 0; i < this.partners.length; i++) {
          if (this.partners[i].sponsored == "1") {
            this.sponsored_items.push(this.partners[i]);
          }
        }
      });
  }


  get_banners() {
    this.getBanners.get_banners(1)
      .then(data => {
        console.log(data);
        this.banners = data.results

        for (var i = 0; i < this.banners.length; i++) {
          this.banners[i].banner = true;
          this.sponsored_items.push(this.banners[i]);
        }
      });
  }

  arrayFilter() {
    console.log(this.sponsored_items);
    this.shuffleArray(this.sponsored_items);
    this.sponsored_items = this.sponsored_items.filter((item, index) => index < 1);
    console.log(this.sponsored_items);

  }

  shuffleArray(array) {
    array.sort(function (a, b) {
      return (0.5 - Math.random());
    });
  }

The function arrayFilter is executed but I need that this.sponsored_items is filled

This is a problem with async data can I resolve with a good pattern?

Thank You!

#2

You can use forkJoin for this.

See this link.

#3

I have two different promises that i retrieve data.
After i retrieve data in two different arrays what is the best way to merged this arrays considering that these are async data?

#4

Use Promise.all, similar to my answer in another thread this morning.

#5

Yep. I usually find sites like Mozilla, etc. more confusing than helpful, but docs on promise.all are actually pretty cut and dry helpful

#6

I would suggest a really simple adjustment - just call the next function after the first function is returned.
Note: because http is async the reference to this is not there but it is easy to get round by with a var beforehand.

It is not as elegant as Promise.all() but is easier to understand if the numbers of calls are not that many.

I have put the adjustments in bold print:

1 Like
#7

Thank You for your solution :slight_smile:

#8

Not sure your shuffle function is ideal - have a look at the following: