React Relay (react-relay) with Typescript throwing TypeError: Object prototype may only be an Object or null: undefined

Question

I'm running into an really bizarre TypeError with react-relay when trying to instantiate a class that extends Relay.Mutation. I've created a simple Typescript project with create-react-app my-app --scripts-version=react-scripts-ts to demonstrate the issue.

Whenever I run yarn start, this is what I'm seeing:

This error doesn't really make sense to me: TypeError: Object prototype may only be an Object or null: undefined

I'm just trying to instantiate a new instance of my own extended Relay.Mutation class. I'm really new to the React Relay world and ES6/Typescript in general so it's likely something silly I'm just missing.

In this simple project I'm using the example class directly as defined in the DefinitelyTyped repository.

Shouldn't I be able to use the class like so:

const atm = new AddTweetMutation({ text: 'asdf', userId: '1123' });

Here is what the AddTweetMutation.tsx class looks like:

import * as Relay from 'react-relay';

interface Props {
  text: string;
  userId: string;
}

interface State {
}

export default class AddTweetMutation extends Relay.Mutation<Props, State> {

  public getMutation() {
    return Relay.QL`mutation{addTweet}`;
  }

  public getFatQuery() {
    return Relay.QL`
            fragment on AddTweetPayload {
                tweetEdge
                user
            }
        `;
  }

  public getConfigs() {
    return [{
      type: 'RANGE_ADD',
      parentName: 'user',
      parentID: this.props.userId,
      connectionName: 'tweets',
      edgeName: 'tweetEdge',
      rangeBehaviors: {
        '': 'append',
      },
    }];
  }

  public getVariables() {
    return this.props;
  }
}

Here is the the entire Hello.tsx React component:

import * as React from 'react';
import AddTweetMutation from '../mutations/AddTweetMutation';

export interface Props {
  name: string;
  enthusiasmLevel?: number;
}

class Hello extends React.Component<Props, {}> {
  render() {

    const atm = new AddTweetMutation({ text: 'asdf', userId: '1123' });
    console.log(atm);

    const { name, enthusiasmLevel = 1 } = this.props;

    if (enthusiasmLevel <= 0) {
      throw new Error('You could be a little more enthusiastic. :D');
    }

    return (
      <div className="hello">
        <div className="greeting">
          Hello {name + getExclamationMarks(enthusiasmLevel)}
        </div>
      </div>
    );
  }
}

export default Hello;

// helpers

function getExclamationMarks(numChars: number) {
  return Array(numChars + 1).join('!');
}

This is what my package.json looks like:

{
  "name": "my-app",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@types/jest": "^20.0.6",
    "@types/node": "^8.0.19",
    "@types/react": "^16.0.0",
    "@types/react-dom": "^15.5.2",
    "@types/react-relay": "^0.9.13",
    "react": "^15.6.1",
    "react-dom": "^15.6.1",
    "react-relay": "^1.1.0",
    "react-scripts-ts": "2.5.0"
  },
  "devDependencies": {},
  "scripts": {
    "start": "react-scripts-ts start",
    "build": "react-scripts-ts build",
    "test": "react-scripts-ts test --env=jsdom",
    "eject": "react-scripts-ts eject"
  }
}

Here's the project to github

Update: The typings are not currently valid for react-relay > 1.x. Please see the thread on github for this issue. I have also updated my repo with the workaround.

Answer 1

The problem is that react-relay@1.1.0 has changed its API and @types/react-relay@0.9.13 is outdated.

TypeScript statically analyze your code based on the typings (type definitions) available. So even thou @types/react-relay@0.9.13 is outdated, TypeScript doesn't know and just act based on it.

To solve this problem, you can either:

• Contribute to @types/react-relay at https://github.com/DefinitelyTyped/DefinitelyTyped to update its typings
• File issue on it at https://github.com/DefinitelyTyped/DefinitelyTyped to see if someone can help updating the typings.
• Update the typings yourself locally using "module augmentation" (https://www.typescriptlang.org/docs/handbook/declaration-merging.html)
• Not using @types/react-relay and do a declare module "react-relay" to mark it as any type (you will lose type safety and IDE support, but if the typings is not correct, it doesn't matter anyway).

For the last option, do this:

// custom-typings/react-relay.d.ts
declare module 'react-relay'

// tsconfig.json
{
  "include": [
    "custom-typings"
  ]
}