simple-schema.js

const simpleSchema = new Schema({
 nodes: {
   doc: {content: "paragraph+"},
   paragraph: {
    content: "inline<_>*",
    group: "block",
    parseDOM: [{tag: "p"}],
    toDOM() { return ["p", 0] }
   },
   text: {
     group: "inline",
     toDOM() { return node.text }
   }
 },
 marks: {
   bold: {
    parseDOM: [{tag: "i"}, {tag: "em"},
     {style: "font-style", getAttrs: value => value == "italic" && null}],
    toDOM() { return ["em"] }
   }
 }
})