When updating static blocks markup and attributes, block authors need to consider existing posts using the old versions of their block. In order to provide a good upgrade path, you can choose one of the following strategies:
- Do not deprecate the block and create a new one (a different name)
- Provide a "deprecated" version of the block allowing users opening these in the block editor to edit them using the updated block.
A block can have several deprecated versions. A deprecation will be tried if a parsed block appears to be invalid, or if there is a deprecation defined for which its isEligible property function returns true.
Deprecations are defined on a block type as its deprecated property, an array of deprecation objects where each object takes the form:
attributes(Object): The attributes definition of the deprecated form of the block.supports(Object): The supports definition of the deprecated form of the block.save(Function): The save implementation of the deprecated form of the block.migrate(Function, Optional): A function which, given the old attributes and inner blocks is expected to return either the new attributes or a tuple array of[ attributes, innerBlocks ]compatible with the block.isEligible(Function, Optional): A function which, given the attributes and inner blocks of the parsed block, returns true if the deprecation can handle the block migration even if the block is valid. This function is not called when the block is invalid. This is particularly useful in cases where a block is technically valid even once deprecated, and requires updates to its attributes or inner blocks.
It's important to note that attributes, supports, and save are not automatically inherited from the current version, since they can impact parsing and serialization of a block, so they must be defined on the deprecated object in order to be processed during a migration.
{% codetabs %} {% ESNext %}
const { registerBlockType } = wp.blocks;
const attributes = {
text: {
type: 'string',
default: 'some random value',
}
};
registerBlockType( 'gutenberg/block-with-deprecated-version', {
// ... other block properties go here
attributes,
save( props ) {
return <div>{ props.attributes.text }</div>;
},
deprecated: [
{
attributes,
save( props ) {
return <p>{ props.attributes.text }</p>;
},
}
]
} );{% ES5 %}
var el = wp.element.createElement,
registerBlockType = wp.blocks.registerBlockType,
attributes = {
text: {
type: 'string',
default: 'some random value',
}
};
registerBlockType( 'gutenberg/block-with-deprecated-version', {
// ... other block properties go here
attributes: attributes,
save: function( props ) {
return el( 'div', {}, props.attributes.text );
},
deprecated: [
{
attributes: attributes,
save: function( props ) {
return el( 'p', {}, props.attributes.text );
},
}
]
} );{% end %}
In the example above we updated the markup of the block to use a div instead of p.
Sometimes, you need to update the attributes set to rename or modify old attributes.
{% codetabs %} {% ESNext %}
const { registerBlockType } = wp.blocks;
registerBlockType( 'gutenberg/block-with-deprecated-version', {
// ... other block properties go here
attributes: {
content: {
type: 'string',
default: 'some random value',
}
},
save( props ) {
return <div>{ props.attributes.content }</div>;
},
deprecated: [
{
attributes: {
text: {
type: 'string',
default: 'some random value',
}
},
migrate( { text } ) {
return {
content: text
};
},
save( props ) {
return <p>{ props.attributes.text }</p>;
},
}
]
} );{% ES5 %}
var el = wp.element.createElement,
registerBlockType = wp.blocks.registerBlockType;
registerBlockType( 'gutenberg/block-with-deprecated-version', {
// ... other block properties go here
attributes: {
content: {
type: 'string',
default: 'some random value',
}
},
save: function( props ) {
return el( 'div', {}, props.attributes.content );
},
deprecated: [
{
attributes: {
text: {
type: 'string',
default: 'some random value',
}
},
migrate: function( attributes ) {
return {
content: attributes.text
};
},
save: function( props ) {
return el( 'p', {}, props.attributes.text );
},
}
]
} );{% end %}
In the example above we updated the markup of the block to use a div instead of p and rename the text attribute to content.
Situations may exist where when migrating the block we may need to add or remove innerBlocks. E.g: a block wants to migrate a title attribute to a paragraph innerBlock.
{% codetabs %} {% ESNext %}
const { registerBlockType } = wp.blocks;
const { omit } = lodash;
registerBlockType( 'gutenberg/block-with-deprecated-version', {
// ... block properties go here
save( props ) {
return <p>{ props.attributes.title }</p>;
},
deprecated: [
{
attributes: {
title: {
type: 'string',
source: 'html',
selector: 'p',
},
},
migrate( attributes, innerBlocks ) {
return [
omit( attributes, 'title' ),
[
createBlock( 'core/paragraph', {
content: attributes.title,
fontSize: 'large',
} ),
...innerBlocks,
],
];
},
save( props ) {
return <p>{ props.attributes.title }</p>;
},
}
]
} );{% ES5 %}
var el = wp.element.createElement,
registerBlockType = wp.blocks.registerBlockType,
omit = lodash.omit;
registerBlockType( 'gutenberg/block-with-deprecated-version', {
// ... block properties go here
deprecated: [
{
attributes: {
title: {
type: 'string',
source: 'html',
selector: 'p',
},
},
migrate: function( attributes, innerBlocks ) {
return [
omit( attributes, 'title' ),
[
createBlock( 'core/paragraph', {
content: attributes.title,
fontSize: 'large',
} ),
].concat( innerBlocks ),
];
},
save: function( props ) {
return el( 'p', {}, props.attributes.title );
},
}
]
} );{% end %}
In the example above we updated the block to use an inner Paragraph block with a title instead of a title attribute.
Above are example cases of block deprecation. For more, real-world examples, check for deprecations in the core block library. Core blocks have been updated across releases and contain simple and complex deprecations.