@ndn/util/lib/timer_node.js

NDNts: general utilities

import assert from "tiny-invariant";
/**
 * Create a random jitter generator function.
 * @param r - Jitter factor around median.
 * @param x - Median value.
 * @returns Jitter generator function.
 *
 * @remarks
 * Each time the returned jitter generator function is called, it returns a number within
 * `[x*(1-r), x*(1+r)]` range. For example, `randomJitter(0.1, 2)` creates a jitter generator
 * function that returns random values within `[1.8, 2.2]` range.
 */
export function randomJitter(r, x = 1) {
    r = Math.max(0, Math.min(r, 1));
    if (r === 0) {
        return () => x;
    }
    const min = 1 - r;
    const distance = 2 * r;
    return () => x * (min + distance * Math.random());
}
(function (randomJitter) {
    /** Create a random generator function between `[min,max]`. */
    function between(min, max) {
        const distance = max - min;
        assert(distance >= 0);
        if (distance === 0) {
            return () => min;
        }
        return () => min + distance * Math.random();
    }
    randomJitter.between = between;
})(randomJitter || (randomJitter = {}));