Patterns for creating custom error types.

custom_error.js

// Pattern for creating a custom error type.
//
// Based on Zakas, Professional Javascript for Web Developers, 3rd Ed., p. 619,
// See also http://stackoverflow.com/a/5251506/508355, including comments.

function MyCustomError ( message ) {
    this.message = message;

    if ( Error.captureStackTrace ) {
        Error.captureStackTrace( this, this.constructor );
    } else {
        this.stack = ( new Error() ).stack;
    }
}

MyCustomError.prototype = Object.create ? Object.create( Error.prototype ) : new Error();
MyCustomError.prototype.name = "MyCustomError";
MyCustomError.prototype.constructor = MyCustomError;


// ------------------------------------------------------------------------


// Generator for custom error types, encapsulating the pattern above.
// 
// Based on http://stackoverflow.com/a/27925672/508355

/**
 * Creates and returns a custom error type.
 *
 * @param   {string} name  of the error type
 * @returns {Error}
 */
function createCustomErrorType ( name ) {

    function CustomError ( message ) {
        this.message = message;

        if ( Error.captureStackTrace ) {
            Error.captureStackTrace( this, this.constructor );
        } else {
            this.stack = ( new Error() ).stack;
        }
    }

    CustomError.prototype = new Error();
    CustomError.prototype.name = name;
    CustomError.prototype.constructor = CustomError;

    return CustomError;
}