Javascript errors to my particular sensibilities.

Usage no npm install needed!

<script type="module">
  import shieldsbetterSberror2 from 'https://cdn.skypack.dev/@shieldsbetter/sberror2';


Shieldsbetter Errors

Javascript errors to my particular sensibilities.


const assert = require('assert');
const SbError = require('@shieldsbetter/sberrors2');

class OutOfCheeseError extends SbError {
    static messageTemplate = 'Cheese port {{port}} is out of {{cheeseType}}.';

const cause = new Error('Cheese delivery late.');

try {
    throw new OutOfCheeseError(cause, {
        port: 5,
        cheeseType: 'gouda',
        deployment: 'turkey sandwich'
catch (e) {
    assert.equal(e.message, 'Cheese port 5 is out of gouda.');
    assert.equal(e.cause, cause);

    assert(e instanceof Error);
    assert(e instanceof SbError);
    assert(e instanceof OutOfCheeseError);

    assert.equal(e.code, 'OUT_OF_CHEESE_ERROR');

    assert.deepEqual(e.details, {
        port: 5,
        cheeseType: 'gouda',
        deployment: 'turkey sandwich'

    assert.equal(e.port, 5);
    assert.equal(e.cheeseType, 'gouda');
    assert.equal(e.deployment, 'turkey sandwich');


Static field messageTemplate will be rendered by the static method renderMessage, which simply wraps Mustache.render() by default.

renderMessage() will be called with two arguments:

  • The message template
  • A details object (which could potentially be undefined but if defined is guaranteed to be an object)

Attempting to instantiate an error without a top-level messageTemplate will yield an SbError.CannotInstantiateAbstract error.

Non-abstract error types may be instantiated with one or both of an Error cause and a details object, in any order.