prosemirror-firebase

Collaborative editing for ProseMirror using Firebase's Realtime Database. Features timestamped and attributed changes, version checkpointing, selection tracking, and more.

usage

Assumes familiarity with ProseMirror and Firebase.

Call new FirebaseEditor with an object containing:

firebaseRef firebase.database.Reference
stateConfig config (must contain schema, doc will be overwritten)
view Function that creates an editor view and returns it. Recieves an object containing:
- stateConfig config to be used for creating the state for new Editor View (or new MenuBarEditorView)
- updateCollab Function that should be called in dispatchTransaction with the transaction and the newState:
```
dispatchTransaction(transaction) {
    let newState = view.state.apply(transaction)
    view.updateState(newState)
    updateCollab(transaction, newState)
},
```
- selections Object with keys being clientIds and values being selections (useful for showing cursors and selections of other clients)
clientId (optional, used to attribute changes and distinguish them from those of other clients, defaults to a unique 120-bit string identifier)

Returns a Promise that resolves when the editor is ready (when existing content has been loaded and an editor view has been created). The resolved value is an object containing the properties and methods of the editor:

view (see above)
selections (see above)
destroy Function that removes all database listeners that were added, removes the client's selection from the database, and calls editorView.destroy

basic

new FirebaseEditor({
    firebaseRef: /*database.Reference*/,
    stateConfig: {
        schema: /*Schema*/,
    },
    view({ stateConfig, updateCollab }) {
        let view = new EditorView(/*dom.Node*/, {
            state: EditorState.create(stateConfig),
            dispatchTransaction(transaction) {
                let newState = view.state.apply(transaction)
                view.updateState(newState)
                updateCollab(transaction, newState)
            },
        })
        return view
    },
})

cursors and selections

function stringToColor(string, alpha = 1) {
    let hue = string.split('').reduce((sum, char) => sum + char.charCodeAt(0), 0) % 360
    return `hsla(${hue}, 100%, 50%, ${alpha})`
}

new FirebaseEditor({
    /*...*/
    view({ stateConfig, updateCollab, selections }) {
        let view = new EditorView(/*dom.Node*/, {
            /*...*/
            decorations({ doc }) {
                return DecorationSet.create(doc, Object.entries(selections).map(
                    function ([ clientID, { from, to } ]) {
                        if (from === to) {
                            let elem = document.createElement('span')
                            elem.style.borderLeft = `1px solid ${stringToColor(clientID)}`
                            return Decoration.widget(from, elem)
                        } else {
                            return Decoration.inline(from, to, {
                                style: `background-color: ${stringToColor(clientID, 0.2)};`,
                            })
                        }
                    }
                ))                  
            },
        })
        return view
    },
})

ready

new FirebaseEditor({
    /*...*/
}).then(({ view, selections, destroy }) => {
    console.log('editor ready')
}).catch(console.error)

license