I am trying to learn typescript/js and one of thing i am doing is implement a rest-api using aws-lambda (severless tack). Now, I need to extract body payload to either a construct or just assign those values to variables.
Lets say I am sending following request to signup a user
POST {{userApiEndpoint}}/signup HTTP/1.1
content-type: application/json
{"username":{{username}},"password":{{password}}}
Now I want to extract this username and password from event.body. I have tried multiple things and everytime i am getting errors of string | undefined can't be assigned to string or something similar.
Things that i have tried
export interface User {
username: string | undefined;
password: string | undefined;
}
Option 1: const newUser = event.body? as User; got an error that says Cannot find name 'as'
Option 2: const newUser = event.body as User; got an error which says Conversion of type 'string | undefined' to type 'User' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.
Option 3: const body = JSON.parse(event.body); got an error which says Argument of type 'string | undefined' is not assignable to parameter of type 'string'.
I am not sure what else to try.
Option 3 should work.
Edit: unless you have explicitly typed your event type as APIGatewayProxyEventV2, in which case the body is of type string | undefined, and the user is:
user = JSON.parse(event.body ?? "") as User
export interface User {
username: string | undefined;
password: string | undefined;
}
// event explicitly typed as APIGatewayProxyEventV2
// the body is typed as string | undefined
const event = {body: '{"username": "foo", "password": "bar"}'} as Record<string, string | undefined>
const user = JSON.parse(event.body ?? "") as User
console.log(user.password)
// Option 3
// the body is typed as any
const event1 = {body: '{"username": "foo", "password": "bar"}'} as Record<string, any>
const user1 = JSON.parse(event1.body) as User
console.log(user1.password)