在 Node 和 Typescript 中的 Firebase 云函数中进行前提条件检查的简单方法是什么？

Question

The goal is to enforce that some required parameter has been successfully passed, it's of the right type and otherwise, throw a correct and informative error.

If-Statements

This works, but requires too much boilerplate code.

export const joinSocialRequest = functions.https.onCall(async (data, context) => {
    const eventId = data.eventId
    if (eventId === undefined) {
       throw new functions.https.HttpsError('unknown','Missing param eventId.')
    }
    ...
}

Using preconditions-ts or preconditions NPM package

This is better, but all errors are thrown as "Internal", which doesn't let my client engineers know what's going on!

import { requiredStringFrom } from 'preconditions-ts';
export const acceptParticipantRequest = functions.https.onCall(async (data, context) => {
    const eventId = requiredStringFrom(data, "eventId")
    ...
}

I can probably wrap the above in a try/catch and throw the correct error, but that means, I will need to write a lot of wrappers!

Is there a better way?

Answer 1

You could write your own validation assertion helper:

function validate(condition, message, code = 'invalid-argument') {
  if (!condition) {
    throw new functions.https.HttpsError(code, message);
  }
}

export const joinSocialRequest = functions.https.onCall(async (data, context) => {
    const eventId = data.eventId
    validate(eventId !== undefined, 'Missing param eventId.');
}