assertFloatEqual.js

const { AssertionError } = require('assert');

/**
 * Adapted from https://github.com/sindresorhus/float-equal
 * License evidence: https://github.com/sindresorhus/float-equal/blob/master/license
 * @author Sindre Sorhus + fork contributions from Alex Birch
 * @license MIT
 * @param {number} a
 * @param {number} b
 * @param {tolerance} b
 */
const assertFloatEqual = (a, b, tolerance = Number.EPSILON) => {
    if (a === b) {
        return;
    }

    const diff = Math.abs(a - b);

    if (diff < tolerance) {
        return;
    }

    if (diff <= tolerance * Math.min(Math.abs(a), Math.abs(b))) {
        return;
    }

    throw new AssertionError({
        operator: `within ${tolerance} of`,
        expected: `${b} (difference: ${diff})`,
        actual: a
    });
};

module.exports = {
    assertFloatEqual
};