scramjet-core/lib/util/stream-errors.js

A pluggable minimal version of Scramjet that focuses only on stream transform and exposes only core features

const os = require("os");
const combineStack = (stack, ...errors) => {
    return errors.reduce(
        (stack, trace) => {
            if (!trace) return stack;
            if (trace.indexOf("\n") >= 0)
                return stack + os.EOL + trace.substr(trace.indexOf("\n") + 1);

            else
                return stack + os.EOL + trace;
        },
        stack
    );
};

class StreamError extends Error {

    constructor(cause, stream, code = "GENERAL", chunk = null) {
        code = cause.code || code;
        stream = cause.stream || stream;
        chunk = cause.chunk || chunk;

        super(cause.message);

        if (cause instanceof StreamError)
            return cause;

        this.chunk = chunk;
        this.stream = stream;
        this.code = "ERR_SCRAMJET_" + code;
        this.cause = cause;

        const stack = this.stack;
        Object.defineProperty(this, "stack", {
            get: function () {
                return combineStack(
                    stack,
                    "  caused by:",
                    cause.stack,
                    `  --- raised in ${stream.name} constructed ---`,
                    stream.constructed
                );
            }
        });

        /** Needed to fix babel errors. */
        this.constructor = StreamError;
        this.__proto__ = StreamError.prototype;
    }

}

/**
 * Stream errors class
 *
 * @module scramjet/errors
 * @prop {Class<StreamError>} StreamError
 * @prop {Function} combineStack
 */
module.exports = {StreamError, combineStack};