I am looking for a way to generate unique random numbers in JavaScript or Typescript.
Currently, I am using the following code:
var id = -((new Date()).getTime() & 0xffff);
This code produces numbers such as -13915 or -28806...
While this method works most of the time, it encounters issues when executed in promises, potentially leading to duplicate IDs being generated.
Is there a reliable solution for generating unique random numbers under all circumstances?
If you're looking for examples, there are plenty to be found online. One way to start is by utilizing the Math.random() function. For instance, you can generate a random number between 1 and 100 with the following code:
Math.floor((Math.random() * 100) + 1);
However, it's important to note that while this method provides randomness, it is not considered secure for cryptographic purposes. In such cases, it would be wise to explore using specialized libraries instead.
Generate a personalized code that is exclusive:
let codes = [];
const uniqueCode = (maxNum) => {
const code = Math.floor((Math.random() * maxNum) + 1);
if (!codes.includes(code)) {
codes.push(code);
return code;
} else if (codes.length - 1 !== maxNum) {
uniqueCode(maxNum);
}
}
const userCode = uniqueCode(100);
console.log(codes) // displays all distinct codes
This will provide a unique code between 1 and 100, ensuring it doesn't exceed the maximum length.
If you're looking to generate unique identifiers in JavaScript, consider using the uuid package:
const uuidv4 = require('uuid/v4');
uuidv4(); // Example output: '10ba038e-48da-487b-96e8-8d3b99b6d18a'
Note that UUIDs are 128-bit numbers and should be treated as strings in JavaScript due to their size.
For browser applications, it's recommended to generate UUIDs from a back-end API for security reasons. Most programming languages have implementations of UUID generation. While the npm package works in browsers, it falls back to Math.random if necessary, which may not be secure.
Learn more about Universally Unique Identifiers (UUIDs) here.
let randomDate = Date.now() + Math.random().toString(36).substr(2, 9);
Using Math.random() should be secure enough due to the use of 64-bit numbers. The likelihood of generating the same number twice is extremely low, even with an imperfect generator.
If you specifically need integers, consider multiplying Math.random() by a large number like Number.MAX_SAFE_INTEGER.
For added safety measures, you can maintain an array of used ids and create a function that continues to draw new unique numbers until one is generated that has not been used before. This value would then be added to the array and returned. It may be beneficial to encapsulate this functionality within a single object, function, or class for organization.
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