Angular: star rating

Question

I would like implement rating star system. After click returns correct value of star. I have a problem with correctly displaying the selected stars. Just like in this picture, it doesn't show me 3 stars in yellow. How to change it? Component:

 export class RatingStarComponent implements OnInit {
  stars: number[] = [1, 2, 3, 4, 5];
  constructor() { }
  ngOnInit() {
  }
  countStar(star) {
    console.log('Value of star', star);
  }
}

HTML:

 <div class="row">
  <div class="col-sm-12">
      <ul class="list-inline rating-list" *ngFor="let star of stars" style="display: inline-block" >
          <li (click)="countStar(star)"><i   class="fa fa-star "></i></li> 
      </ul>
  </div>
</div>

CSS:

  .rating-list li {
  float: right;
  color: #ddd;
  padding: 10px 5px;

}

.rating-list li:hover,
.rating-list li:hover ~ li {
  color: #ffd700;
}

.rating-list {
  display: inline-block;
  list-style: none;
}

Any help or suggestion is welcome.

Answer 1

You have to store the selected value:

countStar(star) {
    this.selectedValue = star;
    console.log('Value of star', star);
}

And add class which will change color of the star for all the stars with less or equal rating:

.rating-list li.selected {
    color: #ffd700;
}

<li (click)="countStar(star)"
    [ngClass]="{'selected': (star <= selectedValue)}">
        <i class="fa fa-star"></i>
</li> 

See full example for the details.

Answer 2

Improved version

In this solution, even on hover all previous stars' colors will change to yellow:

HTML:

<div class="row">
  <div class="col-sm-12">
      <ul class="list-inline rating-list" *ngFor="let star of stars; let i= index" style="display: inline-block"> 
          <li (click)="countStar(star)" id="{{'starId'+i}}" [ngClass]="{'selected': (star <= selectedValue)}" 
           (mouseover)="addClass(star)" (mouseout)="removeClass(star)"> ★
          </li>
      </ul>
  </div>
</div>

Component.ts:

stars: number[] = [1, 2, 3, 4, 5];
selectedValue: number = 0;

countStar(star) {
    this.selectedValue = star;
  }

addClass(star) {
   let ab = "";
   for (let i = 0; i < star; i++) {
     ab = "starId" + i;
     document.getElementById(ab).classList.add("selected");
   }
}
removeClass(star) {
   let ab = "";
   for (let i = star-1; i >= this.selectedValue; i--) {
     ab = "starId" + i;
     document.getElementById(ab).classList.remove("selected");
   }
}

SCSS:

.rating-list {
    li {
    font-size: 20px;
        float: right;
        color: #ddd;
        padding: 10px 5px;
        &:hover {
            color: #ffd700;
            ~ {
                li {
                    color: #ffd700;
                }
            }
        }
    }
    li.selected {
        color: #ffd700;
    }
    display: inline-block;
    list-style: none;
}

See this example for details.