Typescript: TS7006: Parameter 'xxx' implicitly has an 'any' type

Question

In testing my UserRouter, I am using a json file

data.json

[
  {
    "id": 1,
    "name": "Luke Cage",
    "aliases": ["Carl Lucas", "Power Man", "Mr. Bulletproof", "Hero for Hire"],
    "occupation": "bartender",
    "gender": "male",
    "height": {
      "ft": 6,
      "in": 3
    },
    "hair": "bald",
    "eyes": "brown",
    "powers": [
      "strength",
      "durability",
      "healing"
    ]
  },
  {
  ...
  }
]

Building my app, I get the following TS error

ERROR in ...../UserRouter.ts
(30,27): error TS7006: Parameter 'user' implicitly has an 'any' type.

UserRouter.ts

import {Router, Request, Response, NextFunction} from 'express';
const Users = require('../data');

export class UserRouter {
  router: Router;

  constructor() {
  ...
  }

  /**
   * GET one User by id
   */
  public getOne(req: Request, res: Response, _next: NextFunction) {
    let query = parseInt(req.params.id);
 /*[30]->*/let user = Users.find(user => user.id === query);
    if (user) {
      res.status(200)
        .send({
          message: 'Success',
          status: res.status,
          user
        });
    }
    else {
      res.status(404)
        .send({
          message: 'No User found with the given id.',
          status: res.status
        });
    }
  }


}

const userRouter = new UserRouter().router;
export default userRouter;

Answer 1

You are using the --noImplicitAny and TypeScript doesn't know about the type of the Users object. In this case, you need to explicitly define the user type.

Change this line:

let user = Users.find(user => user.id === query);

to this:

let user = Users.find((user: any) => user.id === query); 
// use "any" or some other interface to type this argument

Or define the type of your Users object:

//...
interface User {
    id: number;
    name: string;
    aliases: string[];
    occupation: string;
    gender: string;
    height: {ft: number; in: number;}
    hair: string;
    eyes: string;
    powers: string[]
}
//...
const Users = <User[]>require('../data');
//...