artillery/dist/lib/commons/jitter.js

Cloud-scale load testing. https://www.artillery.io

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// Takes "<number>:<jitter>" (jitter as absolute value or percentage,
// e.g. "1000:20%") and returns a randomized number around the base
// value. Anything else is returned unchanged.
export function jitter(sApprox) {
    if (!sApprox) {
        return sApprox;
    }
    if (typeof sApprox !== 'string') {
        return sApprox;
    }
    if (sApprox.indexOf(':') < 0) {
        return sApprox;
    }
    const inputs = sApprox.split(':');
    const nb = parseInt(inputs[0], 10);
    const approxPercent = parseInt(inputs[1], 10);
    let approx = approxPercent;
    if (inputs[1].indexOf('%') >= 0) {
        approx = (nb * approxPercent) / 100;
    }
    return Math.max(0, nb - approx + Math.random() * 2 * approx);
}