CODEWITHSUNDEEP
node.jstypescript
John Winston
John Winston

Reputation: 1481

if-else cannot type check in Typescript

I am writing an API in Typescript, but I got the error Property 'password' does not exist on type 'unknown' despite the if check.

P.S. the type for request.body is unknown

  login: async (request: FastifyRequest, reply: FastifyReply) => {
    if(!request.body){
      reply.code(400).send({
        message: "Missing request body"
      })
      return
    }

    const { username, password } = request.body

    if(!username || !password){
      reply.code(400).send({
        message: "Missing username or password"
      })
      return
    }

How can I type check this correctly? I can already catch the case where request.body === undefined, is this an issue of Typescript?

Upvotes: 1

Views: 94

Answers (1)

Robert Kawecki
Robert Kawecki

Reputation: 2458

See the documentation on how to specify the body type (and the expected query parameters, and so on) in Fastify: https://www.fastify.io/docs/latest/TypeScript/#request

You'll need to pass parameters to the FastifyRequest generic type, like so:

async (request: FastifyRequest<{
  Body: {
    username: string,
    password: string
  }
}>, reply: FastifyReply)

Upvotes: 3

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