Flow Playground

Built-in Functions

  • fun panic(_ message: String): Never

    Terminates the program unconditionally and reports a message which explains why the unrecoverable error occurred.

    let optionalAccount: AuthAccount? = // ...
    let account = optionalAccount ?? panic("missing account")
  • fun assert(_ condition: Bool, message: String)

    Terminates the program if the given condition is false, and reports a message which explains how the condition is false. Use this function for internal sanity checks.

    The message argument is optional.

  • fun unsafeRandom(): UInt64

    Returns a pseudo-random number.

    NOTE: The use of this function is unsafe if not used correctly.

    Follow best practices to prevent security issues when using this function.