How to generate hash from timestamp?

Question

I must generate unique hash - maybe from timestamp. hash must have max 8 chars. How to do it?

For now I have only timestamp:

var t = new Date().getTime();

You'll have to use some library to generate hash. You can try this: https://code.google.com/p/crypto-js/ — Vivek, Sep 18 '15 at 10:28
[Related: Generate an 8 character hash from an integer](http://stackoverflow.com/questions/2520794/php-generate-an-8-character-hash-from-an-integer) — rgajrawala, Sep 18 '15 at 10:30
possible duplicate of [Create GUID / UUID in JavaScript?](http://stackoverflow.com/questions/105034/create-guid-uuid-in-javascript) — Limnic, Sep 18 '15 at 10:30

score 63 · Accepted Answer · answered Sep 18 '15 at 10:37

63

That may look funny but the following code may work well for the next couple of centuries :)

(+new Date).toString(36);  // "iepii89m"

After that you can extend it with slicing method: (+new Date).toString(36).slice(-8).

answered Sep 18 '15 at 10:37

VisioN

2

And if you wish to minimize the possibility of collision you can try this: `((+new Date) + Math.random()* 100).toString(32)` – Daniel Sokolowski Nov 08 '16 at 15:41
10

@DanielSokolowski Why would it help in minimising the possibility of collision? I'd argue that it's exactly the opposite. – Michal Sep 20 '17 at 14:11
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can you explain what is that + for, very curious – BardZH Dec 12 '19 at 02:18
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@Bardia This is basically a shortcut for `Number(new Date).toString(36)`. See: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators#Unary_plus. – VisioN Dec 12 '19 at 10:08
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Date.now().toString(36) i think this is prettier – Crusader Jul 22 '20 at 12:29
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Great answer here! There's a lot of scenarios where you don't really need UUID but need a unique string based off the progression of time. – Matt Lo Sep 03 '22 at 21:52

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