TypeError: Cannot read property 'on' of undefined

Description

Contributor guide

Tech stack

javascript

Domain

tooling

Issue type

bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-3 hours

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

unclear

Prerequisites

None

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

30

Research direction

The issue reports a TypeError: Cannot read property 'on' of undefined during beautification. The user references a gist for more context. Review the gist (https://gist.github.com/ODCA117/917affd6b11437517535a45350379820) and the comments for reproduction steps. The codebase is written in CoffeeScript; examine the beautify logic to locate where the 'on' property is expected. Since the repository is seeking a maintainer and has limited activity, verify the bug persists on the current version.