Help Typescript detect that the required path parameter hasn’t been filed about scaleway-sdk-js

[Vinzius]

Even if we were to code a function having a different return type depending on the parameter (refactor of validatePathParam below), it would already break in the API methods as the output would be string | something-else and not just string. In our case, we would like an error only when the developer is using the lib, not before that.

export function validatePathParam<T extends string | number | undefined>(
  name: string,
  param: T,
): typeof param extends undefined ? TypeError : string {
  type OutType = typeof param extends undefined ? TypeError : string

  switch (typeof param) {
    case 'string':
      if (param.length === 0) {
        throw new TypeError(`param ${name} cannot be empty in request`)
      }

      return param as unknown as OutType
    case 'number':
      return param.toString() as OutType
    default:
      return new TypeError(`unrecognized type for parameter ${name}`) as OutType
  }
}

This issue mostly concerns path parameters with default value during the client init. A more global change targeting these parameters might be a better option.

[Vinzius]

In short, probably no way to fix at the moment. Will have to revisit the core issue.