percent-value/lib/index.js

Percentage helper functions.

"use strict";

function percentValue(input) {
    input = parseFloat(input);
    return {
        of: function of(total) {
            // input ..... total
            // ?     ..... 100
            total = parseFloat(total);
            return input * 100 / total;
        },
        get: function get(percent) {
            // ?       ..... input
            // percent ..... 100
            percent = parseFloat(percent);
            return percent / 100 * input;
        },
        from: function from(total) {
            // ?        ..... total
            // input    ..... 100
            total = parseFloat(total);
            return percentValue(input).get(total);
        },
        is: function is(howMuch) {
            // howMuch ..... ?
            // input   ..... 100
            howMuch = parseFloat(howMuch);
            return howMuch * 100 / input;
        }
    };
}

module.exports = percentValue;