#Validation

10 snippets

• PHP Tested

  Validate emails and URLs in PHP

  Use filter_var to validate email addresses and http(s) URLs, with an allow-list for schemes.

• TypeScript Tested

  Parse JSON into a typed value with a guard

  Safely turn unknown JSON into a typed result by validating its shape instead of casting.

• TypeScript Tested

  Typed fetch helper that checks the response

  A fetch wrapper that throws on HTTP errors and validates the JSON body with a type guard.

• Python Tested

  Dataclass with validation

  Validate and normalize fields in __post_init__ so invalid objects can never be created.

• PHP Tested

  Decode JSON safely in PHP

  Parse JSON with exceptions on error and a depth limit, instead of silently getting null.

• TypeScript Tested

  A typed Result type for error handling without exceptions

  Model success and failure as a discriminated union so callers must handle both cases.

• TypeScript Tested

  Safely narrow unknown JSON with type guards

  Replace "as any" on parsed JSON with small type guards that check shape at runtime.

• SQL Tested

  Find duplicate rows by one or more columns

  List values that appear more than once with GROUP BY and HAVING, including how many times.

• TypeScript Tested

  Exhaustive switch with assertNever

  Make the compiler fail when a union gains a new member that a switch does not handle.

• HTML

  Accessible form field with label, hint and error

  Associate labels, help text and validation errors with an input so screen readers announce them.