Get SUM of value in Array

Question

I want to get sum of the values in array. With this code when I console.log(this.totalCount) I only get like this .

How to get sum of all the values?

CODE

return this.http
      .post('/media', reqBody)
      .pipe(
        map((res:IStatisticReponse) => res.data)
      ).subscribe(res => {
        this.items = res.map((r: any, i: number) => {
          r.color = this.colors[i]
          return r;
        });

        this.legendProgress = this.items.map(item => {
          return { label: item.label, color: item.color };
        });
        this.totalCount = this.items.map((item)=> item.mediaShare);
        console.log(this.totalCount)

        this.isLoading = false;
      });

The map() method creates a new array populated with the results of calling a provided function on every element in the calling array. so you code must be this.totalCount.length even I not sure why you are using map with empty value — Prashant Pimpale
– Prashant Pimpale, Commented Jan 13, 2020 at 7:39
@OnurGelmez when I add this.items.length I got error (property) Array<any>.length: number Gets or sets the length of the array. This is a number one higher than the highest element defined in an array. This expression is not callable. Type 'Number' has no call signatures.ts(2349) — Pravu
– Pravu, Commented Jan 13, 2020 at 7:43

Philipp Meissner · Accepted Answer · 2020-01-13 07:59:26Z

3

In your current implementation you basically iterate over all items within the items array and return the objects mediaShare property.

this.totalCount = this.items.map((item)=> item.mediaShare); // => ["123", "345", ...]

What you actually want to do is to get the sum of all these values. Considering the values inside totalCount are now a collection of strings that seem to hold a numeric value, you can do the following:

this.totalCount = this.items.map((item)=> Number.parseInt(item.mediaShare)).reduce((acc, curr) => acc + curr, 0); // Or `parseFloat`, if your values might be of type float

Read up on Array.prototype.reduce to learn how it behaves.

edited Jan 13, 2020 at 7:59

answered Jan 13, 2020 at 7:49

Philipp Meissner

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3 Comments

Pravu Over a year ago

Your code only display like this 265619871071 not sum of the value

Pravu Over a year ago

I want it like this ` totalCount = 2656 + 1987 + 1071 `

Philipp Meissner Over a year ago

Which is exactly what I gave you. I added another edit, maybe you checked the code prior to it. Please test it again with the latest solution provided.

agung · Accepted Answer · 2020-01-13 07:48:59Z

1

try this

let totalVal;
for(let i = 0; i < this.totalCount.length; i++) {
  totalVal = totalVal + parseInt(this.totalCount[i]);
}

answered Jan 13, 2020 at 7:48

agung

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