Log the diffs between props in a react component

diffs.js

componentDidUpdate(prevProps) {
    console.log("Render update diff:");

    const now = Object.entries(this.props);
    const added = now.filter(([key, val]) => {
      if (prevProps[key] === undefined && val !== undefined) return true;
      if (prevProps[key] !== val) {
        console.log(`${key}
          + ${JSON.stringify(val)}
          - ${JSON.stringify(prevProps[key])}`);
      }
      return false;
    });
    added.forEach(([key, val]) =>
      console.log(`${key}
          + ${JSON.stringify(val)}
          - undefined`)
    );
  }

For just the prop names, not their whole object

  componentDidUpdate(prevProps) {
    const now = Object.entries(this.props);
    const added = now.filter(([key, val]) => {
      if (prevProps[key] === undefined && val !== undefined) return true;
      if (prevProps[key] !== val) {
        console.count(`${key}`);
      }
      return false;
    });
    added.forEach(([key, val]) => console.count(`${key}`));
  }