prettier/prettier

Support prettier-ignore-start/end for other languages (not only Markdown)

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#5287 opened on Oct 23, 2018

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 (75 comments) (437 reactions) (0 assignees)JavaScript (51,868 stars) (4,716 forks)batch import
area:ignorehelp wanted

Description

It seems this feature was added only for markdown (#4202 cc @ikatyang), but it's actually useful for other languages as well. It is not working on typescript files on my tests.

Related: https://github.com/facebook/create-react-app/issues/5543

Environments:

  • Prettier Version: 1.14.3
  • Running Prettier via: CLI
  • Runtime: Node.js v8.11.4
  • Operating System: macOS

Steps to reproduce:

Create a index.d.ts file with the following content:

// prettier-ignore
type A1 = string;

// prettier-ignore
type A2 = string

/* prettier-ignore-start */
type B1 = string;
type B2 = string
/* prettier-ignore-end */

type C1 = string;
type C2 = string

Expected behavior:

// prettier-ignore
type A1 = string;

// prettier-ignore
type A2 = string

/* prettier-ignore-start */
type B1 = string;
type B2 = string
/* prettier-ignore-end */

-type C1 = string;
+type C1 = string
type C2 = string

Actual behavior:

// prettier-ignore
type A1 = string;

// prettier-ignore
type A2 = string

/* prettier-ignore-start */
-type B1 = string;
+type B1 = string
type B2 = string
/* prettier-ignore-end */

-type C1 = string;
+type C1 = string
type C2 = string

Contributor guide

Tech stack
typescriptjavascript
Domain
developer experiencetooling
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.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Understanding of prettier ignore comments
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
The feature already exists for Markdown (PR #4202). To extend it to TypeScript, examine the Markdown implementation in prettier's source, likely in src/language js/ or src/language markdown/. The logic for parsing 'prettier ignore start/end' comments needs to be added for JavaScript/TypeScript. Check the existing test files for 'prettier ignore' in JavaScript to understand the pattern. The issue includes a clear repro case for a .d.ts file, which can be used for testing.