zod-operators

@lcsga/zod-operators

This package provides a custom RxJS operator, used to empower the use of zod schemas alongside RxJS observables.

• zodParse: This operator is usefull to parse zod schemas within an RxJS stream, in order to check types at runtime.

  zodParse<T, R>(schema: ZodType<R, ZodTypeDef, T>, options?: { strict?: boolean }): OperatorFunction<T, R>

  argument	type	description
  schema	ZodType<R, ZodTypeDef, T>	The schema to provide for the parsing. A description can also be provided to improve the debugging by calling the describe() method to it.
  options	{ strict: boolean }	Optional. Default is {}. A configuration object to modify the behavior of the operator.

  
  

  Example:

  const GithubUserSchema = z.object({
    id: z.string().uuid(),
    login: z.string(),
  });
  
  type GithubUser = z.infer<typeof GithubUserSchema>;
  
  fromFetch<GithubUser[]>('https://api.github.com/users?per_page=5', { selector: (res) => res.json() })
    .pipe(zodParse(GithubUserSchema.array()))
    .subscribe(console.log);

  Since the id of a Github user is of type number and since the zodParse operator is not strict by default, the console.log will return the object fetched without any parsing and the console will print the following warning:

  ZodError: [
    {
      "code": "invalid_type",
      "expected": "string",
      "received": "number",
      "path": [
        0,
        "id"
      ],
      "message": "Expected string, received number"
    },
    {
      "code": "invalid_type",
      "expected": "string",
      "received": "number",
      "path": [
        1,
        "id"
      ],
      "message": "Expected string, received number"
    },
    {
      "code": "invalid_type",
      "expected": "string",
      "received": "number",
      "path": [
        2,
        "id"
      ],
      "message": "Expected string, received number"
    },
    {
      "code": "invalid_type",
      "expected": "string",
      "received": "number",
      "path": [
        3,
        "id"
      ],
      "message": "Expected string, received number"
    },
    {
      "code": "invalid_type",
      "expected": "string",
      "received": "number",
      "path": [
        4,
        "id"
      ],
      "message": "Expected string, received number"
    }
  ]
  

  If we want to throw an error instead of a simple warning, we can pass an options object as the second argument and set strict to true:

  fromFetch<GithubUser[]>('https://api.github.com/users?per_page=5', { selector: (res) => res.json() })
    .pipe(zodParse(GithubUserSchema.array(), { strict: true }))
    .subscribe(console.log);

  The error will be the same as in the warning above, but this time we won't receive any data in the console.log.