calculating the sum of all individual items within an object

Question

calculating the sum of all individual items within an object

Is there a way to map an object, add specific values, and then calculate the total? I am looking to map the object below and extract certain items. Any suggestions?

Object:

  [
    {
        "description": "Current Term",
        "monthlyRent": 29971.599999999995,
        "monthsInPeriod": 41.7,
        "rentInPeriod": null
    },
    {
        "description": "Current Term - Rent Adjustment",
        "monthlyRent": 31470.180000000004,
        "monthsInPeriod": 47.96666666666667,
        "rentInPeriod": 1509519.634
    }
]
29971.599999999995 + 41.7   = 30,012
31470.180000000004 + 47.96666666666667 =  31,517

Desired Result: should be

 total = 30,012 + 31,517

angular typescript

Answer 1

Answer №1

To achieve the desired outcome, you can utilize the map and reduce methods:

const data = [
    {
        "description": "Current Term",
        "monthlyRent": 29971.599999999995,
        "monthsInPeriod": 41.7,
        "rentInPeriod": null
    },
    {
        "description": "Current Term - Rent Adjustment",
        "monthlyRent": 31470.180000000004,
        "monthsInPeriod": 47.96666666666667,
        "rentInPeriod": 1509519.634
    }
];
const total = data
  .map(item => item.monthlyRent * item.monthsInPeriod)
  .reduce((currentValue, acc) => acc + currentValue);

If you prefer to add the monthlyRent and monthsInPeriod instead of multiplying them, simply replace the map with

item.monthlyRent + item.monthsInPeriod

.

Answer 2

To achieve the desired outcome, you can utilize the map and reduce methods:

const data = [
    {
        "description": "Current Term",
        "monthlyRent": 29971.599999999995,
        "monthsInPeriod": 41.7,
        "rentInPeriod": null
    },
    {
        "description": "Current Term - Rent Adjustment",
        "monthlyRent": 31470.180000000004,
        "monthsInPeriod": 47.96666666666667,
        "rentInPeriod": 1509519.634
    }
];
const total = data
  .map(item => item.monthlyRent * item.monthsInPeriod)
  .reduce((currentValue, acc) => acc + currentValue);

If you prefer to add the monthlyRent and monthsInPeriod instead of multiplying them, simply replace the map with

item.monthlyRent + item.monthsInPeriod

.

Answer 3

Answer №2

The map() method generates a fresh array filled with the outcomes of invoking a specified function on each item in the original array. For more details, check out this example.

The reduce() method executes a user-defined “reducer” callback function on every element of the array, using the result from the previous calculation for the current element. The final output of applying the reducer to all elements is a single value. View an example here.

You can create a solution by utilizing both methods like this:

let arry = [
    {
        "description": "Current Term",
        "monthlyRent": 29971.599999999995,
        "monthsInPeriod": 41.7,
        "rentInPeriod": null
    },
    {
        "description": "Current Term - Rent Adjustment",
        "monthlyRent": 31470.180000000004,
        "monthsInPeriod": 47.96666666666667,
        "rentInPeriod": 1509519.634
    }
];

let total = arry 
  .map(obj=> obj.monthlyRent + obj.monthsInPeriod)
  .reduce((value, previousValue) => previousValue + value);

An alternative approach is to simply use a forEach loop:

 let total2:number=0;
    for (let i = 0; i < this.arry.length; i++) {
       let val = this.arry[i].monthlyRent + this.arry[i].monthsInPeriod;
       total2 = total2+val       
    }

Feel free to access the included StackBlitz here.

Answer 4

The map() method generates a fresh array filled with the outcomes of invoking a specified function on each item in the original array. For more details, check out this example.

The reduce() method executes a user-defined “reducer” callback function on every element of the array, using the result from the previous calculation for the current element. The final output of applying the reducer to all elements is a single value. View an example here.

You can create a solution by utilizing both methods like this:

let arry = [
    {
        "description": "Current Term",
        "monthlyRent": 29971.599999999995,
        "monthsInPeriod": 41.7,
        "rentInPeriod": null
    },
    {
        "description": "Current Term - Rent Adjustment",
        "monthlyRent": 31470.180000000004,
        "monthsInPeriod": 47.96666666666667,
        "rentInPeriod": 1509519.634
    }
];

let total = arry 
  .map(obj=> obj.monthlyRent + obj.monthsInPeriod)
  .reduce((value, previousValue) => previousValue + value);

An alternative approach is to simply use a forEach loop:

 let total2:number=0;
    for (let i = 0; i < this.arry.length; i++) {
       let val = this.arry[i].monthlyRent + this.arry[i].monthsInPeriod;
       total2 = total2+val       
    }

Feel free to access the included StackBlitz here.

calculating the sum of all individual items within an object

Answer №1

Answer №2

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