Guide on obtaining the total value from a JSON Array in Angular 2 using TypeScript

Question

Guide on obtaining the total value from a JSON Array in Angular 2 using TypeScript

I received a JSON response which includes carts values with different amounts.

"carts": {
            "value": [
                {

                    "Amt": 40

                },
                {
                    "Amt": 20.25

                },
                {

                    "Amt": 10.30

                }

            ]
        }

My goal is to calculate the sum of all Amt values, which should be 70.55. I am learning TypeScript and would appreciate any help on how to achieve this task.

arrays json angular typescript

Answer 1

Answer №1

For efficient utilization of JavaScript's reduce function (also applicable to TypeScript), follow this structured approach:

const data = {
  "list": {
    "elements": [
      {
        "value": 30
      },
      {
        "value": 15.75
      },
      {
        "value": 7.90
      }
    ]
  }
};

const result = data.list.elements.reduce((total, item) => total + item.value, 0);

console.log(result);

Remember, for compatibility with IE8, it is imperative to integrate a polyfill (as detailed on the MDN documentation).

Answer 2

For efficient utilization of JavaScript's reduce function (also applicable to TypeScript), follow this structured approach:

const data = {
  "list": {
    "elements": [
      {
        "value": 30
      },
      {
        "value": 15.75
      },
      {
        "value": 7.90
      }
    ]
  }
};

const result = data.list.elements.reduce((total, item) => total + item.value, 0);

console.log(result);

Remember, for compatibility with IE8, it is imperative to integrate a polyfill (as detailed on the MDN documentation).

Answer 3

Answer №2

Although the Rxjs' Observable response is a popular choice, it's worth noting that there is an alternative approach using JavaScript arrays and the reduce function, which can also be utilized in Typescript.

// assuming that the variable 'carts' already contains the deserialized JSON
let total: number = carts.value.reduce( 
  (a: number, b) => a + b.Amt, 0);

Following @Stefan's feedback:

Certain mistakes have been corrected, and it is advisable not to assign a type to 'b', allowing for inference based on context and potentially catching any TypeScript errors during compile-time.

Answer 4

Although the Rxjs' Observable response is a popular choice, it's worth noting that there is an alternative approach using JavaScript arrays and the reduce function, which can also be utilized in Typescript.

// assuming that the variable 'carts' already contains the deserialized JSON
let total: number = carts.value.reduce( 
  (a: number, b) => a + b.Amt, 0);

Following @Stefan's feedback:

Certain mistakes have been corrected, and it is advisable not to assign a type to 'b', allowing for inference based on context and potentially catching any TypeScript errors during compile-time.

Answer 5

Answer №3

One way to achieve this is by employing observable reduce function. Suppose you are dealing with an Http response:

this.http.get('url')
    .map(response.items.total)
    .map(res => res.Price)
    .reduce((x, y) => x + y)
    .subscribe(total => console.log(total))

Answer 6

One way to achieve this is by employing observable reduce function. Suppose you are dealing with an Http response:

this.http.get('url')
    .map(response.items.total)
    .map(res => res.Price)
    .reduce((x, y) => x + y)
    .subscribe(total => console.log(total))

Answer 7

Answer №4

const total = 0;
    for (let j = 0; j < this.baskets.value.length; j++) {
        total += this.baskets.value[j].Amount;
    }

Answer 8

const total = 0;
    for (let j = 0; j < this.baskets.value.length; j++) {
        total += this.baskets.value[j].Amount;
    }

Answer 9

Answer №5

If you want to calculate the total cost of items in a shopping cart, you can create a function similar to this:

public calculateCartTotal(): number {
    let totalCost: number = 0;

    this.itemsInCart.forEach((item: any) => {
        totalCost += Number(item.price);
    });

    return totalCost;
}

Answer 10

If you want to calculate the total cost of items in a shopping cart, you can create a function similar to this:

public calculateCartTotal(): number {
    let totalCost: number = 0;

    this.itemsInCart.forEach((item: any) => {
        totalCost += Number(item.price);
    });

    return totalCost;
}

Answer 11

Answer №6

This is the simple method to achieve the desired outcome.

  let total = 0;
  for(const item of json.carts.list){
      total += item.amount;
  }

Answer 12

This is the simple method to achieve the desired outcome.

  let total = 0;
  for(const item of json.carts.list){
      total += item.amount;
  }

Guide on obtaining the total value from a JSON Array in Angular 2 using TypeScript

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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