index.js

// 算法1
function uuid() {
    let s = [];
    let hexDigits = "0123456789abcdef";
    for (let i = 0; i < 36; i++) {
        s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);
    }
    s[14] = "4";        // bits 12-15 of the time_hi_and_version field to 0010
    s[19] = hexDigits.substr((s[19] & 0x3) | 0x8, 1);   // bits 6-7 of the clock_seq_hi_and_reserved to 01
    s[8] = s[13] = s[18] = s[23] = "-";
    let uuid = s.join("");
    return uuid;
}

// 算法 2
function guid() {

    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
        let r
            = Math.random()*16|0, v = c === 'x' ?
            r : (r&0x3|0x8);

        return v.toString(16);

    });
}


//算法3

function guid() {

    function S4() {

        return (((1+Math.random())*0x10000)|0).toString(16).substring(1);

    }

    return (S4()+S4()+"-"+S4()+"-"+S4()+"-"+S4()+"-"+S4()+S4()+S4());

}


// 算法4
function uuid(len, radix) {
    var chars
        = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('');
    var uuid
        = [], i;
    radix
        = radix || chars.length;

    if (len) {
        for (i = 0; i < len; i++) uuid[i] = chars[0 | Math.random()*radix];
    } else {
        var r;
        uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-';
        uuid[14] = '4';
        for (i = 0; i < 36; i++) {

            if (!uuid[i]) {
                r = 0 | Math.random()*16;
                uuid[i] = chars[(i == 19) ? (r & 0x3) | 0x8 : r];
            }
        }
    }
    return uuid.join('');
}