functions git:20250224.001a864A

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---
description: Rules for writing TypeScript functions
globs: *.ts, *.tsx
---
# TypeScript Function Rules

<rule>
name: function_parameters
description: Standards for writing TypeScript function parameters
filters:
  # Match TypeScript and React files
  - type: file_extension
    pattern: "\\.(ts|tsx)$"
  # Match function declarations and expressions
  - type: content
    pattern: "(function|const)\\s+\\w+\\s*=?\\s*(async)?\\s*\\([^)]*\\)"

actions:
  - type: reject
    conditions:
      - pattern: "function\\s+\\w+\\s*\\([^,]*,[^)]+\\)|const\\s+\\w+\\s*=\\s*(async)?\\s*\\([^,]*,[^)]+\\)"
        message: "Functions with more than 1 parameter should use an object parameter"

  - type: suggest
    message: |
      When writing TypeScript functions:

      1. For functions with more than 1 parameter, use an object parameter:
         ```typescript
         // Instead of:
         const myFunction = (id: string, name: string) => {
           // ...
         }

         // Do this:
         type MyFunctionInput = {
           id: string
           name: string
         }

         const myFunction = ({ id, name }: MyFunctionInput) => {
           // ...
         }
         ```

      2. Name the input type with the pattern: `{FunctionName}Input`

      3. For single parameters, direct arguments are acceptable:
         ```typescript
         const getUser = (id: string) => { /* ... */ }
         ```

examples:
  - input: |
      // Bad: Multiple direct parameters
      const updateName = (id: string, newName: string) => {
        // ...
      }

      // Good: Using object parameter
      type UpdateNameInput = {
        id: string
        newName: string
      }

      const updateName = ({
        id,
        newName
      }: UpdateNameInput) => {
        // ...
      }

      // Good: Single parameter
      const getUser = (id: string) => {
        // ...
      }
    output: "Function parameters structured correctly"

metadata:
  priority: high
  version: 1.0
</rule>