parcel-bundler/parcel

Normalize code frames on thrown errors so that `code` always exists

Open

#5115 opened on Sep 8, 2020

View on GitHub
 (3 comments) (0 reactions) (0 assignees)JavaScript (44,030 stars) (2,274 forks)batch import
:raising_hand_woman: FeatureGood First Issue✨ Parcel 2

Description

🙋 feature request

When using the Parcel API and an error is thrown, there's no guarantee that error.diagnostics.*.codeFrame.code exists. If it doesn't then the consumer of the API has to duplicate this logic to retrieve the code pertaining to the code frame:

https://github.com/parcel-bundler/parcel/blob/c4e494f3b9fd0eac672edc1a27c6c9216182dd6b/packages/core/utils/src/prettyDiagnostic.js#L52-L55

This is kind of a pain. I would love to see Parcel normalize these errors so that when a consumer receives a code frame on an error, the code property always exists and the consumer doesn't have to bother with reading source files directly.

🤔 Expected Behavior

I would expect the code property to always exists on any code frame being reported by Parcel.

😯 Current Behavior

The code property only sometimes exists on a code frame.

💁 Possible Solution

If a plugin doesn't provide the code property, Parcel could add it before the error makes its way to the Parcel consumer.

🔦 Context

This is described in further detail in https://github.com/parcel-bundler/parcel/discussions/5081.

💻 Examples

Contributor guide

Tech stack
javascriptnodejs
Domain
cliapibuild system
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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.
clear
Prerequisites
Familiarity with Parcel APIJavaScriptError handling in Node.js
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Investigate the prettyDiagnostic.js file at packages/core/utils/src/prettyDiagnostic.js, specifically lines 52-55 where code is conditionally read. Understand the error diagnostics flow to ensure that code property is always populated. Consider adding a normalization step early in the error handling pipeline to set code from the source file if not provided by the plugin.