font-size for tiptap 2

font-size.ts

import { Extension } from "@tiptap/core";
import "@tiptap/extension-text-style";

export type FontSizeOptions = {
  types: string[];
};

declare module "@tiptap/core" {
  interface Commands<ReturnType> {
    fontSize: {
      /**
       * Set the font size
       */
      setFontSize: (fontSize: string) => ReturnType;
      /**
       * Unset the font size
       */
      unsetFontSize: () => ReturnType;
    };
  }
}

export const FontSize = Extension.create<FontSizeOptions>({
  name: "fontSize",

  addOptions() {
    return {
      types: ["textStyle"],
    };
  },

  addGlobalAttributes() {
    return [
      {
        types: this.options.types,
        attributes: {
          fontSize: {
            default: null,
            parseHTML: (element) =>
              element.style.fontSize.replace(/['"]+/g, ""),
            renderHTML: (attributes) => {
              if (!attributes.fontSize) {
                return {};
              }

              return {
                style: `font-size: ${attributes.fontSize}`,
              };
            },
          },
        },
      },
    ];
  },

  addCommands() {
    return {
      setFontSize:
        (fontSize) =>
        ({ chain }) => {
          return chain().setMark("textStyle", { fontSize }).run();
        },
      unsetFontSize:
        () =>
        ({ chain }) => {
          return chain()
            .setMark("textStyle", { fontSize: null })
            .removeEmptyTextStyle()
            .run();
        },
    };
  },
});

This is an extension for setting the font size in a tiptap 2 editor.
The original code for this was taken from tiptap's fontFamily
The docs for using the extension are exactly the same as the font family docs, just change "fontFamily" to "fontSize" everywhere (match the case of the original).