next.js/examples/with-slate/CustomKeygenEditor/index.js

import React from 'react'
import Plain from 'slate-plain-serializer'
import { KeyUtils } from 'slate'
import { Editor } from 'slate-react'

class CustomKeygenEditor extends React.Component {
  constructor (props) {
    super(props)
    let key = 0
    const keygen = () => {
      key += 1
      return props.uniqueId + key // custom keys
    }
    KeyUtils.setGenerator(keygen)
    this.initialValue = Plain.deserialize(props.content)
  }
  render () {
    return <Editor placeholder='Enter some plain text...' defaultValue={this.initialValue} style={this.props.style} />
  }
}

export default CustomKeygenEditor