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Javascript – Adding percentage to subtotal

I am trying to write a script that will add 5% to a subtotal and no matter what I try it won’t work. Here is an example. I know Excel formulas, but don’t write Javascript, please help.

// (Function added as source of dummy data)
function getField(key) {
    return ({
        EXTENSION1: {value:'110.0'},
        EXTENSION2: {value:'95.0'},
        EXTENSION3: {value:'85.0'},
        EXTENSION4: {value:'65.0'},
        EXTENSION5: {},
        'GE%': {value: '5'},
    })[key]
}

var extension1 = this.getField("EXTENSION1").value;
var extension2 = this.getField("EXTENSION2").value;
var extension3 = this.getField("EXTENSION3").value;
var extension4 = this.getField("EXTENSION4").value;
var extension5 = this.getField("EXTENSION5").value;

var sum = parseFloat(extension1) + parseFloat(extension2) + parseFloat(extension3) + parseFloat(extension4) + parseFloat(extension5);

var percentage = parseFloat(this.getField("GE%").value);

var result = sum * (percentage / 100);

console.log(result);

I’ve entered this code and it’s not producing a value

enter image description here

Tags:

2

Answers


  1. 0

    I have created this snippet to implement your solution and it works for me:

    let extension1 = 0;
let extension2 = 110;
let extension3 = 95;
let extension4 = 85;
let extension5 = 65;
let percentage = 5.5;

var sum = parseFloat(extension1) + parseFloat(extension2) + parseFloat(extension3) + parseFloat(extension4) + parseFloat(extension5);

var result = sum * ((100 + percentage) / 100);

console.log(result);

    Key ideas:

    • you should make sure that your extension values are proper values. If you have non-numeric values to any of them, the result will be NaN
    • you multiply sum with percentage / 100, but you want to add that to sum, which means that you need 100 + percentage instead of just `percentage
    • make sure you use the result
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  2. 0

    Your code doesn’t properly account for when a field hasn’t been filled out.

    A better solution

    You can use detect if a value is NaN and instead set it to 0. The parts I edited are between the markers.

    // (Function added as source of dummy data)
function getField(key) {
    return ({
        EXTENSION1: {value:'110.0'},
        EXTENSION2: {value:'95.0'},
        EXTENSION3: {value:'85.0'},
        EXTENSION4: {value:'65.0'},
        EXTENSION5: {},
        'GE%': {value: '5'},
    })[key]
}

var extension1 = this.getField("EXTENSION1").value;
var extension2 = this.getField("EXTENSION2").value;
var extension3 = this.getField("EXTENSION3").value;
var extension4 = this.getField("EXTENSION4").value;
var extension5 = this.getField("EXTENSION5").value;

// ------------------------
const inputArray = [
    extension1,
    extension2,
    extension3,
    extension4,
    extension5,
];
const sum = inputArray.reduce(
    (accumulator, currentValue) => {
        let val = parseFloat(currentValue);
        if (isNaN(val)) {
            val = 0;
        }
        return accumulator + val;
    },
    0
);
// ------------------------

var percentage = parseFloat(this.getField("GE%").value);

var result = sum * (percentage / 100);

console.log(result);

    An okay solution

    Your updated summation code could simply fail-over to 0 if the string is empty.

    var sum = parseFloat(extension1 || 0) + parseFloat(extension2 || 0) + parseFloat(extension3 || 0) + parseFloat(extension4 || 0) + parseFloat(extension5 || 0);

    Why?

    Passing an empty string to parseInt results in NaN:

    parseFloat('')
> NaN

Likewise, `NaN` plus anything is still `NaN`:
```js
parseFloat('') + 1
> NaN
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