Replace one element in an Array of Angular model objects with another object using Angular2

Question

I have an array of angular objects. I want to replace an entire element in the array with another element.

    export interface modelCourse{
         var1: number;
         var2: number;
     }

I want to do something like this:

    updateResults(myCourse: modelCourse) {
        this.allCourses.forEach(element => {
            if (myCourse.Id=== element.Id) {
                element = myCourse;  // this part doesn't work as expected
            }
        });
    }

Where

    allCourses: modelCourse[] = [];

And allCourses holds all my courses.

Possible duplicate of How to change value of object which is inside an array using JavaScript or jQuery? — nircraft
– nircraft, Commented Dec 18, 2018 at 19:40

DeborahK · Accepted Answer · 2018-12-18 19:58:38Z

3

If you only need to find the one matching element, you don't need to loop through all of the elements, just use the findIndex method. This finds the index of the one element you need without looping through all of them.

You can then use that index to update the original array.

updateResults(myCourse: modelCourse) {
    const foundElementIndex = this.allCourses.findIndex(element => myCourse.id === element.id);
    this.allCourses[foundElementIndex] = myCourse;
}

I did a stackblitz here: https://stackblitz.com/edit/angular-hxxddn

edited Dec 18, 2018 at 19:58

answered Dec 18, 2018 at 19:33

DeborahK

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2 Comments

M Jenkins Over a year ago

Thanks DeborahK. However I'm confused on how that replaces the course in my array with myCourse?

DeborahK Over a year ago

I did a stackblitz. See revised answer.

RANJIT PATRA · Accepted Answer · 2018-12-18 19:39:06Z

0

Please use Array.map to update this.allCourses.

updateResults(myCourse: modelCourse) {
  this.allCourses = this.allCourses.map(element => {
      if (myCourse.Id === element.Id) {
          return myCourse;
      }
      return element;
  });
}

answered Dec 18, 2018 at 19:39

RANJIT PATRA

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