How to modify code so it doesn't run on reload?

Question

This code,

function dec2hex(dec) {
    return dec < 10 ? "0" + String(dec) : dec.toString(16);
  }
  function generateId(len) {
    var arr = new Uint8Array((len || 40) / 2);
    window.crypto.getRandomValues(arr);
    return Array.from(arr, dec2hex).join("");
  }
  var random = generateId(64);
  document.getElementById("password").innerHTML = random;

setInterval(function() {
  function dec2hex(dec) {
    return dec < 10 ? "0" + String(dec) : dec.toString(16);
  }
  function generateId(len) {
    var arr = new Uint8Array((len || 40) / 2);
    window.crypto.getRandomValues(arr);
    return Array.from(arr, dec2hex).join("");
  }
  var random = generateId(64);
  document.getElementById("password").innerHTML = random;
}, 5000);

<div id="password"></div>

will generate a random string every 5 seconds. However, it generate a new string when the page is reloaded. How can I make it NOT generate a random sting on a reload? I have not gotten anything with searches due to the limited queries.

Does this answer your question? [Persist variables between page loads](https://stackoverflow.com/questions/29986657/persist-variables-between-page-loads) — John Montgomery, Nov 16 '20 at 20:09
Are you looking for `clearInterval`? Also, you are running `var random = generateId(64);` before your `setInterval`, so it's going to run because you are calling it. — gen_Eric, Nov 16 '20 at 20:10
@daddygames: I don't get what you mean? Can you make an example? — LegitCoder, Nov 16 '20 at 20:19
@RocketHazmat: I know. Its because the code won't show until 5 seconds are over. — LegitCoder, Nov 16 '20 at 20:19
@LegitCoder What do you mean? The code shows as soon as your code runs, then another code is shown 5 seconds later. What _exactly_ are you trying to do here? — gen_Eric, Nov 16 '20 at 20:22
If you reload the code than it generates a new string even though 5 seconds aren't over — LegitCoder, Nov 16 '20 at 20:24

Obzi · Accepted Answer · 2020-11-16T21:09:20.293

You may use LocalStorage.
The code may look like :

var lastTimeGenerated = window.localStorage.getItem('lastTimeGenerated') === null
    ? false
    : parseInt(window.localStorage.getItem('lastTimeGenerated'));
var generateInterval = 5000;

function dec2hex(dec) {
    return dec < 10 ? "0" + String(dec) : dec.toString(16);
}

function generateId(len) {
    var arr = new Uint8Array((len || 40) / 2);
    window.crypto.getRandomValues(arr);
    return Array.from(arr, dec2hex).join("");
}

function launchIntervalFnc() {
    intervalFnc();
    setInterval(intervalFnc, generateInterval);
}

function intervalFnc() {
    var random = generateId(64);
    document.getElementById("password").innerHTML = random;
    window.localStorage.setItem('lastTimePassword', random);
    window.localStorage.setItem('lastTimeGenerated', new Date().getTime());
}

if (lastTimeGenerated !== false && lastTimeGenerated + generateInterval > new Date().getTime()) {
    document.getElementById("password").innerHTML = window.localStorage.getItem('lastTimePassword');
    setTimeout(launchIntervalFnc, generateInterval - (new Date().getTime() - lastTimeGenerated));
} else {
    launchIntervalFnc();
}

<div id="password"></div>

But i want the string to stay the same after a reload. sorry for my picky situation — LegitCoder, Nov 16 '20 at 20:58
No problem, you just need to save it into the `localStorage`. Code updated — Obzi, Nov 16 '20 at 21:10

How to modify code so it doesn't run on reload?

1 Answers1