Restify next(err) don't serialize extraneous options created by makeConstructor

[deguich]

When sending error with next(error) callback, response sent to client does not contain optionnal properties of my new Error Object created with makeConstructor restify-errors module.

Env : Node v12.18.3 with ESM loader (type: "module") in package.json

Example :

import errs from 'restify-errors';
const TestError = errs.makeConstructor("TestError", {
   statusCode: 500, 
   info: {errcode: "ERR_GENERIC"},
   message:"App Error"
});
const tmp = new TestError();
console.log("tmp.info exists : ", JSON.stringify(tmp.info)); 
console.log("But this is sent to client when next(tmp) called : ", JSON.stringify(tmp)); 

Print :

tmp.info exists : {"errcode":"ERR_GENERIC"}
But this is sent to client when next(tmp) called : {"code":"Test","message":"App Error"}

It seems to be caused by JSON.stringify that only check for ownProperties (it don't look for prototype chain).

[deguich]

I finally used this workaround :

import errs from 'restify-errors';

const toJSONf= function() {
    let tmp = {};
    for(let key in this) {
        if(typeof this[key] !== 'function' && !key.startsWith('jse_') && key!=="body")
            tmp[key] = this[key];
    }
    return tmp;
}

const TestError = errs.makeConstructor("TestError", {
    statusCode: 500, 
    info: {errcode: "ERR_GENERIC"},
    message:"App Error",
    toJSON: toJSONf
});