sindresorhus/eslint-plugin-unicorn

Rule proposal: `no-blob-to-file`

Closed

#1,270 opened on May 13, 2021

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help wantednew rule

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Description

Many people don't know File implements Blob, the only difference is File has .name ..lastModified in most cases don't need convert to File.

Fail

const file = new File([blob], {name: '1.jpg'});
formData.append('file', file);

const file = new File([blob], {name: '1.jpg'});
URL.createObjectURL(file);

Pass

formData.append('file', blob, '1.jpg');

URL.createObjectURL(blob);

This rule might need type info.

Contributor guide

Research direction
Study existing rules in the eslint plugin unicorn repository, particularly those involving type information (e.g., 'no array instanceof'). The rule needs to detect `new File([blob], ...)` and suggest using `blob` directly. Check the TypeScript ESLint parser integration if type info is required. See the issue discussion for any additional context. Implement the rule following the plugin's structure, add tests in the test directory, and update the documentation.
Tech stack
javascript
Domain
toolingdeveloper experience
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.
Half day
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
ESLint plugin development knowledgeAST manipulation
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70