CODEWITHSUNDEEP
typescriptexpress
kennarddh
kennarddh

Reputation: 2665

How to use express.js req.params with typescript

I have express.js controller and I can't use req.params

The error is Property 'id' is missing in type 'ParamsDictionary' but required in type 'IParam'.

I need to get id from param with type string

import { Request, Response } from 'express'

interface IParam {
    id: string
}

const Update = (req: Request, res: Response) => {
    const { id }: IParam = req.param // The error occured here
}

export default Update

Upvotes: 3

Views: 2096

Answers (3)

davR7
davR7

Reputation: 83

I know this question is very old, but I would like to leave my contribution. Below is my solution:

import { ParamsDictionary as Params } from "express-serve-static-core";

export interface IRequestParams<T extends Params> extends Request {
  params: T;
}

Upvotes: 0

Phil
Phil

Reputation: 164744

Your main issue is that you're trying to cast req.params.id (a string) as IParam (an object).

You can typically just use this...

const { id } = req.params;

because Express defines the default params type as

export interface ParamsDictionary {
    [key: string]: string;
}

Otherwise, you can strongly type the Request to include your params

const Update = (req: Request<IParam>, res: Response) => {
  const { id } = req.params;
}

Upvotes: 5

tenshi
tenshi

Reputation: 26326

You should probably use a type assertion here:

interface IParam {
    id: string
}

const Update = (req: Request, res: Response) => {
    const { id } = req.param as unknown as IParam
}

export default Update

An assertion tells TypeScript that you know what you're doing. Previously, you had a type annotation, so TypeScript was really eager to jump in and check the assignment.

Upvotes: 1

Related Questions