How to Create a Permanent Unique ID for Your WordPress Block

Unique light in a row of light bulbs

My previous tutorial focused on creating a unique ID for your WordPress block at runtime. However, this ID isn’t permanent.

Within this tutorial, I’ll show you how to create a permanent unique ID that also works with block duplication.

Step 1: Add a uniqueId attribute

Head to your block’s block.json file and add in the uniqueId attribute. Give it a type of string with an empty default.

Add the uniqueId attribute to your block's attributes
Sample Block.json With the uniqueId Attribute

Step 2: Add a uniqueIds array above your component

In your block’s block code, add a const of uniqueIds above your component.

uniqueIds JS const
uniqueIds JS const

This variable is important because we need to keep track of all of our block IDs globally so that we can generate a new ID in the event the block is duplicated.

// For storing unique IDs.
const uniqueIds = [];Code language: JavaScript (javascript)

Step 3: Grab the block’s clientId

The block’s clientId is a unique string passed to each block at runtime and at block generation. This ID always changes, but you can use it to generate a unique ID for your block.

Client ID in passed props
Client ID in passed props

Step 4: Grab the uniqueId attribute

Grab the uniqueId attribute. We’re going to need it later.

Unique ID attribute
Unique ID attribute
const {
} = attributes;Code language: JavaScript (javascript)

Step 5: Add a useEffect to set the uniqueId

We’ll use useEffect to set the uniqueId if it doesn’t exist. If the uniqueId already exists in our array variable uniqueIds (note the plurality), then a new ID is generated.

Unique ID setting in UseEffect
Unique ID setting in UseEffect
 * Get a unique ID for the block for inline styling if necessary.
useEffect( () => {
	if ( ( null === uniqueId || '' === uniqueId ) || uniqueIds.includes( uniqueId ) ) {
		const newUniqueId = 'wppic-' + clientId.substr( 2, 9 ).replace( '-', '' );

		setAttributes( { uniqueId: newUniqueId } );
		uniqueIds.push( newUniqueId );
	} else {
		uniqueIds.push( uniqueId );
}, [] );Code language: JavaScript (javascript)

This code does the following:

  1. Looks for the uniqueId attribute. If it’s blank or is stored in uniqueIds, then a new ID is generated.
  2. Generates the newUniqueId based on the clientId and a prefix.
  3. Updates the uniqueId attribute and pushes to uniqueIds array for storage.
  4. If the uniqueId is already set, add to the uniqueIds array for storage.

So at first render, a new ID is generated, is checked against existing IDs, and a unique ID is generated.

In the event of block duplication, the uniqueId would have already been added to the uniqueIds array, so a duplicate would be found, and a new unique ID is generated.

Step 6: Add the ID to Your Block Output

Adding a uniqueId to the block output in the id attribute
Add the uniqueId value to your block output

Step 7: Style Your Block

Example Style Output Code
Example Style Output Code

Step 8: Style the Frontend

The Frontend can use the uniqueId as well

That’s it!

Please comment below if you have any questions.

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Ronald Huereca
By: Ronald Huereca
Published On: on September 29, 2023

Ronald Huereca founded DLX Plugins in 2022 with the goal of providing deluxe plugins available for download. Find out more about DLX Plugins, check out some tutorials, and check out our plugins.

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