Store the percentage of an incrementing subset against a total.
yarn add percentage-incrementor or npm i --save percentage-incrementor
const PercentageIncrementor = require('percentage-incrementor');
// Store the percentage of truthy values incremented.
const truthyPercent = new PercentageIncrementor(val => !!val);
// Starts at 0.
truthyPercent.valueOf();
// 0
truthyPercent.increment(false).valueOf();
// 0
truthyPercent.increment(true).valueOf();
// 0.5
truthyPercent.increment(true).valueOf();
// 0.666666666
// Use it as a primitive.
if (truthyPercent > 0.5) {
console.log('yay!');
}
// yay!