Schema

Last updated 2 months ago

Every Slate editor has a "schema" associated with it, which contains information about the structure of its content. For the most basic cases, you'll just rely on Slate's default core schema. But for advanced use cases you can enforce rules about what the content of a Slate document can contain.

Properties

{
document: Object,
blocks: Object,
inlines: Object,
}

The top-level properties of a schema all give you a way to define validation "rules" that the schema enforces.

document

Object

{
document: {
nodes: [{ types: ['paragraph'] }]
}
}

A set of validation rules that apply to the top-level document.

blocks

Object

{
blocks: {
list: {
nodes: [{ types: ['item'] }]
},
item: {
parent: { types: ['list'] }
},
}
}

A dictionary of blocks by type, each with its own set of validation rules.

inlines

Object

{
inlines: {
emoji: {
isVoid: true,
nodes: [{ objects: ['text'] }]
},
}
}

A dictionary of inlines by type, each with its own set of validation rules.

Rule Properties

{
data: Object,
first: Object,
isVoid: Boolean,
last: Object,
nodes: Array,
marks: Array,
normalize: Function,
parent: Object,
text: RegExp,
}

Slate schemas are built up of a set of validation rules. Each of the properties will validate certain pieces of the document based on the properties it defines.

data

Object

{
data: {
href: v => isUrl(v),
}
}

A dictionary of data attributes and their corresponding validation functions. The functions should return a boolean indicating whether the data value is valid or not.

first

Object

{
first: { types: ['quote', 'paragraph'] },
}

Will validate the first child node. The first definition can declare objects and types properties.

isVoid

Boolean

{
isVoid: true,
}

Will validate a node's isVoid property.

last

Object

{
last: { types: ['quote', 'paragraph'] },
}

Will validate the last child node. The last definition can declare objects and types properties.

nodes

Array

{
nodes: [
{ types: ['image', 'video'], min: 1, max: 3 },
{ types: ['paragraph'], min: 0 },
]
}

Will validate a node's children. The nodes definitions can declare the objects, types, min and max properties.

🤖 The nodes array is order-sensitive! The example above will require that the first node be either an image or video, and that it be followed by one or more paragraph nodes.

marks

Array

{
marks: ['italic']
}

Will validate a node's marks. The marks definitions can declare a list of marks type to be allowed. If declared, any marks that are not in the list will be removed.

normalize

normalize(change: Change, violation: String, context: Object) => Void

{
normalize: (change, violation, context) => {
switch (violation) {
case 'child_object_invalid':
change.wrapBlockByKey(context.child.key, 'paragraph')
return
case 'child_type_invalid':
change.setNodeByKey(context.child.key, 'paragraph')
return
}
}
}

A function that can be provided to override the default behavior in the case of a rule being invalid. By default Slate will do what it can, but since it doesn't know much about your schema, it will often remove invalid nodes. If you want to override this behavior, and "fix" the node instead of removing it, pass a custom normalize function.

For more information on the arguments passed to normalize, see the Violations reference.

parent

Array

{
parent: {
types: ['list']
}
}

Will validate a node's parent. The parent definition can declare the objects and/or types properties.

text

Array

{
text: /^\w+$/
}

Will validate a node's text.

Static Methods

Schema.create

Schema.create(properties: Object) => Schema

Create a new Schema instance with properties.

Schema.fromJSON

Schema.fromJSON(object: Object) => Schema

Create a schema from a JSON object.

Schema.isSchema

Schema.isSchema(maybeSchema: Any) => Boolean

Returns a boolean if the passed in argument is a Schema.

Instance Methods

toJSON

toJSON() => Object

Returns a JSON representation of the schema.

Violations

When supplying your own normalize property for a schema rule, it will be called with (change, violation, context). The violation will be one of a set of potential violation strings, and context will vary depending on the violation.

A set of the invalid violation strings are available as constants via the slate-schema-violations package.