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Defining Custom Block Nodes
Applying Custom Formatting
In the previous guide we learned how to create custom block types that render chunks of text inside different containers. But Slate allows for more than just "blocks".
In this guide, we'll show you how to add custom formatting options, like bold, italic, code or strikethrough.
So we start with our app from earlier:
const CodeNode = (props) => {
return <pre><code>{props.children}</code></pre>
}
const ParagraphNode = (props) => {
return <p>{props.children}</p>
}
class App extends React.Component {
constructor(props) {
super(props)
this.state = {
state: initialState
}
}
render() {
return (
<Editor
state={this.state.state}
renderNode={node => this.renderNode(node)}
onChange={state => this.onChange(state)}
onKeyDown={e, state => this.onKeyDown(e, state)}
/>
)
}
renderNode(node) {
switch (node.type) {
case 'code': return CodeNode
case 'paragraph': return ParagraphNode
}
}
onChange(state) {
this.setState({ state })
}
onKeyDown(event, state) {
if (event.which != 192 || !event.metaKey) return
const isCode = state.blocks.some(block => block.type == 'code')
return state
.transform()
.setBlock(isCode ? 'paragraph' : 'code')
.apply()
}
}
}
And now, we'll edit the onKeyDown handler to make it so that when you press ⌘-B, it will add a "bold" mark to the currently selected text:
class App extends React.Component {
constructor(props) {
super(props)
this.state = {
state: initialState
}
}
render() {
return (
<Editor
state={this.state.state}
renderNode={node => this.renderNode(node)}
onChange={state => this.onChange(state)}
onKeyDown={(e, state) => this.onKeyDown(e, state)}
/>
)
}
renderNode(node) {
if (node.type == 'paragraph') return ParagraphNode
}
onChange(state) {
this.setState({ state })
}
onKeyDown(event, state) {
if (!event.metaKey) return
// Decide what to do based on the key code...
switch (event.which) {
// When "B" is pressed, add a "bold" mark to the text.
case 66: {
return state
.transform()
.mark('bold')
.apply()
}
// When "`" is pressed, keep our existing code block logic.
case 192: {
const isCode = state.blocks.some(block => block.type == 'code')
return state
.transform()
.setBlock(isCode ? 'paragraph' : 'code')
.apply()
}
}
}
}
Okay, so we've got the hotkey handler setup... but! If you happen to now try selecting text and hitting ⌘-B, you'll get an error in your console. That's because we haven't told Slate how to render a "bold" mark.
For every mark type you want to add to your schema, you need to give Slate a "renderer" for that mark, just like nodes. Except unlike nodes, mark renderers are just simple objects of styles that will be passed directly to React's style= property.
So let's define our bold mark:
// Define a set of styles that make text bold.
const BOLD_MARK = {
fontWeight: 'bold'
}
Pretty simple, right?
And now, let's tell Slate about that mark. To do that, we'll need to pass in a renderMark function to the Editor, which it will call with any mark it finds. And when it calls it with a bold mark, we'll return our BOLD_MARK styles. Like so:
const BOLD_MARK = {
fontWeight: 'bold'
}
class App extends React.Component {
constructor(props) {
super(props)
this.state = {
state: initialState
}
}
// Add the `renderMark` handler to the editor.
render() {
return (
<Editor
state={this.state.state}
renderMark={mark => this.renderMark(mark)}
renderNode={node => this.renderNode(node)}
onChange={state => this.onChange(state)}
onKeyDown={(e, state) => this.onKeyDown(e, state)}
/>
)
}
// Define a mark rendering function that knows about "bold" marks.
renderMark(mark) {
if (mark.type == 'bold') return BOLD_MARK
}
renderNode(node) {
if (node.type == 'paragraph') return ParagraphNode
}
onChange(state) {
this.setState({ state })
}
onKeyDown(event, state) {
if (!event.metaKey) return
switch (event.which) {
case 66: {
return state
.transform()
.mark('bold')
.apply()
}
case 192: {
const isCode = state.blocks.some(block => block.type == 'code')
return state
.transform()
.setBlock(isCode ? 'paragraph' : 'code')
.apply()
}
}
}
}
Now, if you try selecting a piece of text and hitting ⌘-B you should see it turn bold! Magic!
But we forgot one thing. When you hit ⌘-B again, it should remove the bold formatting. To do that, we'll need to add a bit of logic to either add or remove the bold mark depending on what the currently selected marks on the text are:
const BOLD_MARK = {
fontWeight: 'bold'
}
class App extends React.Component {
constructor(props) {
super(props)
this.state = {
state: initialState
}
}
render() {
return (
<Editor
state={this.state.state}
renderMark={mark => this.renderMark(mark)}
renderNode={node => this.renderNode(node)}
onChange={state => this.onChange(state)}
onKeyDown={(e, state) => this.onKeyDown(e, state)}
/>
)
}
renderMark(mark) {
if (mark.type == 'bold') return BOLD_MARK
}
renderNode(node) {
if (node.type == 'paragraph') return ParagraphNode
}
onChange(state) {
this.setState({ state })
}
onKeyDown(event, state) {
if (!event.metaKey) return
switch (event.which) {
case 66: {
// Loop through the current marks, check to see if any are bold.
const isBold = state.marks.some(mark => mark.type == 'bold')
return state
.transform()
[isBold ? 'unmark' : 'mark']('bold')
.apply()
}
case 192: {
const isCode = state.blocks.some(block => block.type == 'code')
return state
.transform()
.setBlock(isCode ? 'paragraph' : 'code')
.apply()
}
}
}
}
Now when you repeatedly press ⌘-B you should see the bold formatting be added and removed!
Next:
Using Plugins