JSSM, a JavaScript state machine - the FSM for FSL
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    Class JssmError

    Custom error class for jssm. Enriches the standard Error with machine context (current state, instance name) and an optional requested_state so that error messages are self-describing.

    When a semantic error is detected during compile() and the parse tree was produced with parse(input, { locations: true }), the thrown error also carries a source_location field — the FSL source span of the offending statement — so downstream tooling can map the error to a precise position in the original source text without additional scanning.

    throw new JssmError(machine, 'no such state', { requested_state: 'Blue' });
    // JssmError: [[my-light]]: no such state (at "Red", requested "Blue")

    The Machine instance that raised the error, or undefined if no machine is available. Used to read state() and instance_name() for context.

    A human-readable description of the error.

    Optional JssmErrorExtendedInfo with extra context such as requested_state and/or source_location (the FSL source span of the offending statement, present when the error originated from a located parse tree).

    Hierarchy (View Summary)

    Index
    constructor
    base_message message name requested_state source_location stack? stackTraceLimit
    captureStackTrace prepareStackTrace
    base_message: string
    message: string
    name: string
    requested_state: string
    source_location: FslSourceLocation
    stack?: string
    stackTraceLimit: number

    The Error.stackTraceLimit property specifies the number of stack frames collected by a stack trace (whether generated by new Error().stack or Error.captureStackTrace(obj)).

    The default value is 10 but may be set to any valid JavaScript number. Changes will affect any stack trace captured after the value has been changed.

    If set to a non-number value, or set to a negative number, stack traces will not capture any frames.

    • Creates a .stack property on targetObject, which when accessed returns a string representing the location in the code at which Error.captureStackTrace() was called.

      const myObject = {};
      Error.captureStackTrace(myObject);
      myObject.stack;  // Similar to `new Error().stack`

      The first line of the trace will be prefixed with ${myObject.name}: ${myObject.message}.

      The optional constructorOpt argument accepts a function. If given, all frames above constructorOpt, including constructorOpt, will be omitted from the generated stack trace.

      The constructorOpt argument is useful for hiding implementation details of error generation from the user. For instance:

      function a() {
        b();
      }

      function b() {
        c();
      }

      function c() {
        // Create an error without stack trace to avoid calculating the stack trace twice.
        const { stackTraceLimit } = Error;
        Error.stackTraceLimit = 0;
        const error = new Error();
        Error.stackTraceLimit = stackTraceLimit;

        // Capture the stack trace above function b
        Error.captureStackTrace(error, b); // Neither function c, nor b is included in the stack trace
        throw error;
      }

      a();

      Parameters

      • targetObject: object
      • OptionalconstructorOpt: Function

      Returns void

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