Rule Catalog

Get confused what ast-grep is? This is a list of rewriting rule to inspire you! Explore the power of ast-grep with these rewriting rules that can transform your code in seconds.

Feel free to join our Discord channel or ask Codemod AI to explain the rules for you line by line!

📚 Example Language

CC++DartGoHTMLJavaKotlinPythonRubyRustTSXTypeScriptYAML

📏 Used Rule

atomic

patternkindregex

relational

insidehasfollowsprecedes

composite

allanynotmatches

Example Type

PatternYAML

💡 More Features

Features

rewriterstransformconstraintsutilslabels

Rule List (63) Sort by: NameLangComplexity

• Append formatted bytes with `fmt.Appendf`

  📏pattern

  💡constraints
  🛠️ Fix 📚 Go

  Try in Playground →
• Avoid `&&` short circuit in JSX

  📏kindhasnot
  🛠️ Fix 📚 TSX

  Try in Playground →
• Avoid Duplicated Exports

  📏allpatterninsidehas
  📚 Rust

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• Avoid nested links

  📏patternhas
  📚 TSX

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• Avoid Unnecessary React Hook

  📏anypattern+1

  💡utilsconstraints
  📚 TSX

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• Beware of char offset when iterate over a string

  📝Simple Pattern Example
  🛠️ Fix 📚 Rust

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• Combine checks and trims with `CutPrefix` or `CutSuffix`

  📏allpattern+2

  💡constraintstransform
  🛠️ Fix 📚 Go

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• Detect Path Traversal Vulnerability in Rails

  📏anypattern
  📚 Ruby

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• Detect problematic defer statements with function calls

  📝Simple Pattern Example
  📚 Go

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• Detect problematic JSON tags with dash prefix

  📏patterninside

  💡constraints
  📚 Go

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• Ensure Clean Architecture

  📏pattern

  💡constraints
  📚 Kotlin

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• Extract i18n Keys

  📏kindpatternnot
  🛠️ Fix 📚 HTML

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• Find Dart Calls by Callee Name

  📏anyallkindhas
  📚 Dart

  Try in Playground →
• Find function declarations with names of certain pattern

  📏kindhas
  📚 Go

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• Find Import File without Extension

  📏regexkindanyinside
  📚 TypeScript

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• Find Import Identifiers

  📏anyallkindhasinside+2
  📚 TypeScript

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• Find Import Usage

  📏kindpatterninside
  📚 TypeScript

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• Find Java field declarations of type String

  📏kindhas
  📚 Java

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• Find key/value and Show Message

  📏anypattern
  📚 YAML

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• Find loops that can range over an integer

  📏pattern

  💡constraints
  📚 Go

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• Find map copy loops that may use `maps.Copy`

  📏pattern

  💡constraints
  📚 Go

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• Find Struct Inheritance

  📝Simple Pattern Example
  📚 C++

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• Fix Format String Vulnerability

  📏pattern

  💡constraints
  🛠️ Fix 📚 C++

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• Get number of digits in a `usize`

  📝Simple Pattern Example
  🛠️ Fix 📚 Rust

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• Match Function Call in C

  📏pattern
  📚 C

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• Match Function Call in Golang

  📏pattern
  📚 Go

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• Match package import in Golang

  📏kindhas
  📚 Go

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• Migrate action_filter in Ruby on Rails

  📏anypattern+1

  💡transform
  🛠️ Fix 📚 Ruby

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• Migrate OpenAI SDK

  📏pattern
  🛠️ Fix 📚 Python

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• Migrate XState to v5 from v4

  📏regexpattern+4

  💡utilstransform
  🛠️ Fix 📚 TypeScript

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• Missing Component Decorator

  📏patterninside

  💡constraintslabels
  📚 TypeScript

  Try in Playground →
• No `await` in `Promise.all` array

  📏patterninside
  🛠️ Fix 📚 TypeScript

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• No `console` except in `catch` block

  📏anypattern+1

  💡constraints
  🛠️ Fix 📚 TypeScript

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• No Unused Vars in Java

  📏kindallhasnot
  🛠️ Fix 📚 Java

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• Prefer `any` over `interface{}`

  📏pattern
  🛠️ Fix 📚 Go

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• Prefer `reflect.TypeFor`

  📏pattern
  🛠️ Fix 📚 Go

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• Prefer `slices.Clip`

  📏pattern

  💡constraints
  🛠️ Fix 📚 Go

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• Prefer `slices.Reverse`

  📏pattern

  💡constraints
  🛠️ Fix 📚 Go

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• Prefer `time.Since`

  📏pattern
  🛠️ Fix 📚 Go

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• Prefer Generator Expressions

  📏patternkind

  💡transform
  🛠️ Fix 📚 Python

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• Prefer Symbol over Proc

  📏pattern

  💡constraints
  🛠️ Fix 📚 Ruby

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• Recursive Rewrite Type

  📏kindpattern

  💡rewriterstransform
  🛠️ Fix 📚 Python

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• Refactor pytest fixtures

  📏kindfollows+1

  💡utils
  📚 Python

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• Remove `async` function

  📏pattern

  💡rewriterstransform
  🛠️ Fix 📚 Python

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• Remove redundant range-variable copies

  📏allpatterninside
  🛠️ Fix 📚 Go

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• Rename SVG Attribute

  📏patternregex+2

  💡transform
  🛠️ Fix 📚 TSX

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• Replace delete-all loops with `clear`

  📏pattern
  🛠️ Fix 📚 Go

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• Reverse React Compiler™

  📏anypattern
  🛠️ Fix 📚 TSX

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• Rewrite `indoc!` macro

  📝Simple Pattern Example
  🛠️ Fix 📚 Rust

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• Rewrite `Optional[Type]` to `Type | None`

  📏pattern
  🛠️ Fix 📚 Python

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• Rewrite Check to Yoda Condition

  📏patterninside

  💡constraints
  🛠️ Fix 📚 C

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• Rewrite Method to Function Call

  📏pattern

  💡transform
  🛠️ Fix 📚 C

  Try in Playground →
• Rewrite MobX Component Style

  📏pattern
  🛠️ Fix 📚 TSX

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• Rewrite SQLAlchemy with Type Annotations

  📏patternany

  💡rewriterstransform
  🛠️ Fix 📚 Python

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• Rust 2024 Let-Chain Candidate

  📏matcheshas+5

  💡utils
  📚 Rust

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• Speed up Barrel Import

  📏pattern

  💡rewriterstransform
  🛠️ Fix 📚 TypeScript

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• Stream split results with `SplitSeq` and `FieldsSeq`

  📏pattern

  💡constraintstransform
  🛠️ Fix 📚 Go

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• Switch Chai from `should` style to `expect`

  📏anypattern
  🛠️ Fix 📚 TypeScript

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• Unnecessary `useState` Type

  📝Simple Pattern Example
  🛠️ Fix 📚 TSX

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• Unsafe Function Without Unsafe Block

  📏allkindhasnot
  📚 Rust

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• Upgrade Ant Design Vue

  📏kindregex+2

  💡utilsconstraints
  🛠️ Fix 📚 HTML

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• Use Logical Assignment Operators

  📝Simple Pattern Example
  📚 TypeScript

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• Use Walrus Operator in `if` statement

  📏patternfollows
  🛠️ Fix 📚 Python

  Try in Playground →