emberjs/ember.js

Unreachable code "reached" when trying to render a non-string with the component helper

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#18,072 opened on Jun 4, 2019

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BugGood for New ContributorsHas ReproductionHelp Wanted

Description

Ember Twiddle

Ember Twiddle doesn't let me go above 3.4, but I'm reproducing this on a 3.10 app (during a migration from 2.18).

This is less of a bug and more of something that could have a helpful debug assertion. Maybe something like:

You passed [Object object] to the {{component}} helper, but the component helper only accepts strings or other components.

Along with maybe a log of what that object was.

(This might not be the right repo for this, since it seems to deal with glimmervm internals)

Contributor guide

Tech stack
javascript
Domain
frontend
Issue type
feature
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.
mostly clear
Prerequisites
basic Ember.js knowledgeunderstanding of component helper
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
The issue requests adding a debug assertion when a non string/non component is passed to the {{component}} helper. The relevant code likely resides in ember.js's glimmer packages, specifically the component helper implementation. Look for files in packages/ember glimmer that handle the component helper, such as lib/component.js or similar. The existing error handling for invalid arguments should be located, and a new assertion can be added following Ember's debugging patterns. Check if there are any existing tests for the component helper to ensure the new assertion is covered.