Function invariant

  • Asserts that a given condition is true. If the condition is false, an error is thrown with the provided message.

    Parameters

    • condition: unknown

      The condition to evaluate.

    • Optionalmessage: string

      The error message to throw if the condition is false.

    Returns asserts condition

    Returns void if the condition is true.

    Throws an error if the condition is false.

    // This call will succeed without any errors
    invariant(true, 'This should not throw');

    // This call will fail and throw an error with the message 'This should throw'
    invariant(false, 'This should throw');

    // Example of using invariant with a condition
    invariant(condition, 'Expected condition is false');

    // Ensure that the value is neither null nor undefined
    invariant(value !== null && value !== undefined, 'Value should not be null or undefined');

    // Example of using invariant to check if a number is positive
    invariant(number > 0, 'Number must be positive');