Repository: louislam/uptime-kuma
File: src/util.js (JavaScript)

Code before:
 * The value is no lower than min (or the next integer greater than min
 * if min isn't an integer) and no greater than max (or the next integer
 * lower than max if max isn't an integer).
 * Using Math.round() will give you a non-uniform distribution!
 */
function getRandomInt(min, max) {
    min = Math.ceil(min);
    max = Math.floor(max);
    return Math.floor(Math.random() * (max - min + 1)) + min;
}
exports.getRandomInt = getRandomInt;
function getCryptoRandomInt(min, max) {
    const randomBuffer = new Uint32Array(1);
    crypto.getRandomValues(randomBuffer);
    const randomNumber = randomBuffer[0] / (0xffffffff + 1);
    min = Math.ceil(min);
    max = Math.floor(max);
    return Math.floor(randomNumber * (max - min + 1)) + min;
}
exports.getCryptoRandomInt = getCryptoRandomInt;
function genSecret(length = 64) {
    let secret = "";
    const chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
    const charsLength = chars.length;
    for ( let i = 0; i < length; i++ ) {
        secret += chars.charAt(getCryptoRandomInt(0, charsLength));
    }
    return secret;
}
exports.genSecret = genSecret;
function getMonitorRelativeURL(id) {
    return "/dashboard/" + id;
}
exports.getMonitorRelativeURL = getMonitorRelativeURL;


Review comment (bug):
Off by one error here. The new random int function is min&max inclusive. This should be charsLength-1

Code after:
 * The value is no lower than min (or the next integer greater than min
 * if min isn't an integer) and no greater than max (or the next integer
 * lower than max if max isn't an integer).
 * Using Math.round() will give you a non-uniform distribution!
 */
function getRandomInt(min, max) {
    min = Math.ceil(min);
    max = Math.floor(max);
    return Math.floor(Math.random() * (max - min + 1)) + min;
}
exports.getRandomInt = getRandomInt;
/**
 * Returns either the NodeJS crypto.randomBytes() function or its
 * browser equivalent implemented via window.crypto.getRandomValues()
 */
let getRandomBytes = ((typeof window !== 'undefined' && window.crypto)
    // Browsers
    ? function () {
        return (numBytes) => {
            let randomBytes = new Uint8Array(numBytes);
            for (let i = 0; i < numBytes; i += 65536) {
                window.crypto.getRandomValues(randomBytes.subarray(i, i + Math.min(numBytes - i, 65536)));
            }
            return randomBytes;
        };
    }
    // Node
    : function () {
        return require("crypto").randomBytes;
    })();
function getCryptoRandomInt(min, max) {
    // synchronous version of: https://github.com/joepie91/node-random-number-csprng
    const range = max - min;
    if (range >= Math.pow(2, 32))
        console.log("Warning! Range is too large.");
    let tmpRange = range;
    let bitsNeeded = 0;
    let bytesNeeded = 0;
    let mask = 1;
    while (tmpRange > 0) {
        if (bitsNeeded % 8 === 0)
            bytesNeeded += 1;
        bitsNeeded += 1;
        mask = mask << 1 | 1;
        tmpRange = tmpRange >>> 1;
    }
    const randomBytes = getRandomBytes(bytesNeeded);
    let randomValue = 0;
    for (let i = 0; i < bytesNeeded; i++) {
        randomValue |= randomBytes[i] << 8 * i;
    }