how can i generate randome number using replace function javascript?

Question

i'm new to javascript i need to generate random number using replace it is possible i try

function generateUUID() {
    var dt = new Date().getTime()
    var uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace('/[xy]/g', function (c) {
        var r = (dt + Math.random() * 16) % 16 | 0
        dt = Math.floor(dt / 16)
        return (c == 'x' ? r : (r & 0x3 | 0x8)).toString(16)
    })
    return uuid
}

this function always return xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx What am i missing ?

Answer 1

You're using a string rather than a RegExp in the replace function, this should be a simple fix, e.g. just change

.replace('/[xy]/g',

to

.replace(/[xy]/g,

function generateUUID() {
    var dt = new Date().getTime()
    var uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function (c) {
        var r = (dt + Math.random() * 16) % 16 | 0
        dt = Math.floor(dt / 16)
        return (c == 'x' ? r : (r & 0x3 | 0x8)).toString(16)
    })
    console.log("uuid",uuid)
    return uuid
}

console.log(generateUUID())

I'd also suggest looking at third-party libraries for this purpose, uuid for example, it uses cryptographically-strong random values.

function generateUUID() {
    return uuid.v4();
}
console.log(generateUUID());

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