Add a reading time estimate to all your Contentful rich text nodes in GatsbyJS

gatsby-node.js

exports.onCreateNode = async options => {
  return Promise.all([
    require("./gatsby-onCreateNode-readingTime").onCreateNode(options)

    // add your other onCreateNode functions here
  ]);
};

gatsby-onCreateNode-readingTime.ts

import { documentToPlainTextString } from "@contentful/rich-text-plain-text-renderer";
import readingTime from "reading-time";
import { GatsbyNode } from "gatsby";

export const onCreateNode: GatsbyNode["onCreateNode"] = async ({
  node,
  loadNodeContent,
  actions
}) => {
  const { internal } = node;
  const { owner, mediaType } = internal;
  if (mediaType !== "text/richtext" || owner !== "gatsby-source-contentful") {
    return;
  }
  const doc = JSON.parse(await loadNodeContent(node));
  const text = documentToPlainTextString(doc);
  const result = readingTime(text);
  actions.createNodeField({ node, name: "readingTime", value: result });
};

GatsbyContentfulWithReadingTime.graphql

{
  contentfulBlogPost {
    body {
      fields {
        readingTime {
          text
          minutes
          time
          words
        }
      }
    }
  }
}

Thank you for creating this gist, it was instrumental in getting this adding to my Gatsby site. Great gist!

I get "SyntaxError: Unexpected token {" from gatsby-onCreateNode-readingTime.js

What version of gatsby-source-contentful are you using? I always get Error: Could not find function loadNodeContent for plugin gatsby-source-contentful on line 15