Block development basics in Wordpress - Mini Project: Build & Apply

Block development basics

📖 Scenario: You are creating a simple custom block for the WordPress block editor. This block will display a greeting message that can be customized by the user.

🎯 Goal: Build a basic WordPress block that registers a block named greeting-block and displays a customizable greeting message inside the editor and on the site.

📋 What You'll Learn

Create a block registration with registerBlockType using the name myplugin/greeting-block.

Add an attribute called message of type string with a default value.

Use the edit function to show a text input for the message attribute.

Use the save function to output the greeting message inside a p tag.

💡 Why This Matters

🌍 Real World

Custom blocks let WordPress users add tailored content easily in the block editor, improving site flexibility and user experience.

💼 Career

Knowing block development is essential for WordPress developers creating themes and plugins that extend editor capabilities.

1

Create block registration with initial attributes

Write the code to register a block using registerBlockType with the name myplugin/greeting-block. Add an attribute called message of type string with the default value 'Hello, world!'.

Wordpress

// Register the block with name and attributes
// Your code here

Hint

Use wp.blocks.registerBlockType with the block name and an attributes object containing message.

2

Add edit function with text input for message

Add an edit function to the block registration that uses props.attributes.message and props.setAttributes. Inside, return a TextControl component from wp.components that updates the message attribute when changed.

Wordpress

wp.blocks.registerBlockType('myplugin/greeting-block', {
  attributes: {
    message: {
      type: 'string',
      default: 'Hello, world!'
    }
  },
  // Add edit function here
  // Your code here
});

Hint

Use TextControl from wp.components inside the edit function to let users change the message.

3

Add save function to output the message

Add a save function to the block registration that returns a p element containing the message attribute value.

Wordpress

const { TextControl } = wp.components;

wp.blocks.registerBlockType('myplugin/greeting-block', {
  attributes: {
    message: {
      type: 'string',
      default: 'Hello, world!'
    }
  },
  edit: (props) => {
    const { attributes: { message }, setAttributes } = props;
    return (
      wp.element.createElement(TextControl, {
        label: 'Greeting message',
        value: message,
        onChange: (newMessage) => setAttributes({ message: newMessage })
      })
    );
  },
  // Your code here
});

Hint

The save function should return a p tag with the message text using wp.element.createElement.

4

Complete block registration with all parts

Ensure the block registration includes the attributes, edit, and save functions exactly as specified. The block name must be myplugin/greeting-block. The edit function uses TextControl to edit message. The save function outputs the message inside a p tag.

Wordpress

const { TextControl } = wp.components;

wp.blocks.registerBlockType('myplugin/greeting-block', {
  attributes: {
    message: {
      type: 'string',
      default: 'Hello, world!'
    }
  },
  edit: (props) => {
    const { attributes: { message }, setAttributes } = props;
    return (
      wp.element.createElement(TextControl, {
        label: 'Greeting message',
        value: message,
        onChange: (newMessage) => setAttributes({ message: newMessage })
      })
    );
  },
  save: (props) => {
    const { attributes: { message } } = props;
    return wp.element.createElement('p', null, message);
  }
});
// Your code here

Hint

Double-check that all parts are included and the block name is correct.

Practice

1. What is the main purpose of creating blocks in WordPress block development?

easy

A. To create reusable content pieces that users can add visually

B. To write PHP code for custom themes

C. To manage user roles and permissions

D. To optimize database queries

Solution

1. Step 1: Understand the role of blocks in WordPress

   Blocks are designed to let users add content pieces easily without coding each time.

2. Step 2: Identify the main benefit of blocks

   Blocks are reusable and visually manageable content units improving editing experience.

3. Final Answer:

   To create reusable content pieces that users can add visually -> Option A

4. Quick Check:

   Blocks = reusable visual content [OK]

Hint: Blocks are for reusable visual content pieces [OK]

Common Mistakes:

• Confusing blocks with PHP theme coding
• Thinking blocks manage users or database
• Assuming blocks are only for styling

2. Which function is used to register a new block type in WordPress block development?

easy

A. createBlockType()

B. initBlock()

C. addBlock()

D. registerBlockType()

Solution

1. Step 1: Recall the standard WordPress block registration function

   The official function to register blocks is registerBlockType.

2. Step 2: Verify other options are incorrect

   Functions like createBlockType, addBlock, and initBlock do not exist in WordPress block API.

3. Final Answer:

   registerBlockType() -> Option D

4. Quick Check:

   Register blocks = registerBlockType() [OK]

Hint: Remember: registerBlockType() registers blocks [OK]

Common Mistakes:

• Using createBlockType() which is not a WordPress function
• Confusing with addBlock() or initBlock() which don't exist
• Misspelling the function name

3. Given this block registration code snippet, what will the block display in the editor?

registerBlockType('myplugin/example', {
  edit: () => {
    return 
Hello, WordPress!
;
  },
  save: () => {
    return 
Hello, WordPress!
;
  }
});

medium

A. A paragraph with text 'Hello, WordPress!' in both editor and saved content

B. An empty block with no content

C. A syntax error preventing block registration

D. A block showing 'edit' text only

Solution

1. Step 1: Analyze the edit function output

   The edit function returns a paragraph with 'Hello, WordPress!' which shows in the editor.

2. Step 2: Analyze the save function output

   The save function returns the same paragraph, so saved content also shows 'Hello, WordPress!'.

3. Final Answer:

   A paragraph with text 'Hello, WordPress!' in both editor and saved content -> Option A

4. Quick Check:

   Edit and save return same paragraph = A paragraph with text 'Hello, WordPress!' in both editor and saved content [OK]

Hint: Edit and save return same JSX content means same display [OK]

Common Mistakes:

• Thinking edit content differs from saved content
• Assuming syntax error due to JSX
• Confusing block output with empty or error

4. Identify the error in this block registration code:

registerBlockType('myplugin/test', {
  edit: () => {
    return 
Test Block
;
  },
  save: () => {
    return div>Test Block;
  }
});

medium

A. edit function missing return statement

B. Missing opening < in save function JSX

C. registerBlockType function name is incorrect

D. Block name 'myplugin/test' is invalid

Solution

1. Step 1: Check the save function JSX syntax

   The save function returns div>Test Block; which is missing the opening < for the div tag.

2. Step 2: Verify other parts are correct

   The edit function correctly returns JSX with <div>, the function name is correct, and block name format is valid.

3. Final Answer:

   Missing opening < in save function JSX -> Option B

4. Quick Check:

   JSX tags must start with < [OK]

Hint: Check JSX tags start with < and end with > [OK]

Common Mistakes:

• Ignoring missing < in JSX tags
• Thinking function names or block names are wrong
• Overlooking return statements

5. You want to create a block that shows a dynamic greeting with a user name passed as an attribute. Which approach correctly uses attributes in block development?

hard

A. Hardcode the user name inside the save function JSX

B. Use a global variable for the name inside edit and save functions

C. Define attributes in registerBlockType and use props.attributes.name in edit and save

D. Only define attributes in edit function, ignore save function

Solution

1. Step 1: Understand attribute usage in blocks

   Attributes must be declared in registerBlockType and accessed via props.attributes in both edit and save functions.

2. Step 2: Evaluate other options

   Using global variables or hardcoding breaks reusability and dynamic behavior; ignoring attributes in save causes data loss.

3. Final Answer:

   Define attributes in registerBlockType and use props.attributes.name in edit and save -> Option C

4. Quick Check:

   Attributes declared and used properly = Define attributes in registerBlockType and use props.attributes.name in edit and save [OK]

Hint: Declare and use attributes via props in edit and save [OK]

Common Mistakes:

• Using global variables instead of attributes
• Hardcoding values losing flexibility
• Not using attributes in save function