Adding a total property at the row level in JavaScript

Here is a JavaScript array that I need help with:

[{ Year:2000, Jan:1, Feb: }, {Year:2001, Jan:-1, Feb:0.34 }]

I want to calculate the total of Jan and Feb for each entry in the existing array and add it as a new property.

For example:

[{ Year:2000, Jan:1, Feb:, Total: 1 }, {Year:2001, Jan:2, Feb:4, Total: -0.66 }]

Can someone provide guidance on how to achieve this using JavaScript?

UPDATE: The array now includes decimal values

Answer №1

When interpreting Feb as having a value of 0 when empty, this code will successfully execute.

var data = [{ Year:2000, Jan:1, Feb:0 }, {Year:2001, Jan:2, Feb:4 }];

data.forEach(item => {
    item.Total = item.Jan + item.Feb;
});


console.log(data); /* [
  { Year: 2000, Jan: 1, Feb: 0, Total: 1 },
  { Year: 2001, Jan: 2, Feb: 4, Total: 6 }
]*/


Answer №2

Consider this scenario:

const data = [{ Year:2000, Jan:1, Feb: 2}, {Year:2001, Jan:2, Feb:4 }];

An easy solution is to loop through the months.

data.forEach(item => item.Total = item.Jan + item.Feb)

If needed, you can include more months in the calculation

data.forEach(item => item.Total = item.Jan + item.Feb + item.Mar + item.Apr)

Answer №3

Assume that the variable data holds an array of objects.

const data = [{ Year:2000, Jan:1, Feb: }, {Year:2001, Jan:2, Feb:4 }]

To modify the existing array, you can utilize Array.forEach.

data.forEach((item) => {
    const total = (item.Jan || 0) + (item.Feb || 0);
    item.Total = total;
});

In this scenario, (item.Jan || 0) ensures a default value of 0 for undefined Jan.

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