Code Snippets - uniqueId

I recently had to remove underscore from a repository I was working on and I end up using some small tweaks with plain JS syntax instead. I have to say this is not the first time I do a similar job and I always use the same utility methods here and there.

For that reason, I'm gonna share some of those in my blog for future reference whenever I need one of them again.

It could be you came here for the same reason as me. We'd better share that knowledge 😉

uniqueId

Generates a unique global id for elements that need one.

Examples:

• Setting key property when looping an array in ReactJS (watchout for potential performance issues if going this path!).
• Setting id attribute to DOM elements.
• Cache response from endpoints that don't provide you with an identifier.

As a curried function, it keeps a local counter variable and for every new uniqueId generated counter's value is incremented. An optional prefix can also be sent in case you want some extra information alongside with the id.

function createUniqueId() {
  let counter = 0

  return (prefix = '') => {
    if (prefix) {
      return `${prefix}_${++counter}`
    }

    return `${++counter}`
  }
}

const uniqueId = createUniqueId()

console.log(uniqueId()) // 1
console.log(uniqueId()) // 2
console.log(uniqueId()) // 3
console.log(uniqueId('testing')) // testing_4

I hope that's helpful and interesting to you. 👋🏼