useConsistentTypeDefinitions

TypeScript and TSX

Summary

Rule available since: v2.1.4
Diagnostic Category: lint/style/useConsistentTypeDefinitions
This rule isn’t recommended, so you need to enable it.
This rule has an unsafe fix.
The default severity of this rule is information.
Sources:
- Same as @typescript-eslint/consistent-type-definitions

How to configure

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{
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  "linter": {
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    "rules": {
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      "style": {
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        "useConsistentTypeDefinitions": "error"
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      }
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    }
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  }
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}

Description

Enforce type definitions to consistently use either interface or type.

TypeScript provides two different ways to define an object type: interface and type.

This rule enforces consistent usage of either interface or type for object type definitions. Consistent type definition styles, aside from improving code readability, help minimize cognitive load when developers switch between different codebases or within a large codebase.

Empty object type declarations will be left as-is and will not be converted to interfaces, as it will conflict with the noEmptyInterface rule.

Example

Invalid

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type Point = { x: number; y: number; };

code-block.ts:1:1 lint/style/useConsistentTypeDefinitions  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ Use of the type detected.
  
  > 1 │ type Point = { x: number; y: number; };
      │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    2 │ 
  
  ℹ The codebase should use a consistent coding style for the definition of types. This improves the readability and consistency.
  
  ℹ Unsafe fix: Use interface.
  
    1   │ - type·Point·=·{·x:·number;·y:·number;·};
      1 │ + interface·Point·{
      2 │ + ····x:·number;
      3 │ + ····y:·number;
      4 │ + }
    2 5 │

Valid

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interface Point {
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  x: number;
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  y: number;
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}

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type AnyObject = {};

Options

The following options are available

`style`

This option will determine which style to use for type definitions.

Default: interface

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{
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  "linter": {
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    "rules": {
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      "style": {
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        "useConsistentTypeDefinitions": {
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          "options": {
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            "style": "type"
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          }
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        }
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      }
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    }
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  }
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}

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interface Point {
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  x: number;
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  y: number;
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}

code-block.ts:1:1 lint/style/useConsistentTypeDefinitions  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ Use of the interface detected.
  
  > 1 │ interface Point {
      │ ^^^^^^^^^^^^^^^^^
  > 2 │   x: number;
  > 3 │   y: number;
  > 4 │ }
      │ ^
    5 │ 
  
  ℹ The codebase should use a consistent coding style for the definition of types. This improves the readability and consistency.
  
  ℹ Unsafe fix: Use type alias.
  
    1   │ - interface·Point·{
      1 │ + type·Point·=·{
    2 2 │     x: number;
    3 3 │     y: number;
    4   │ - }
      4 │ + };
    5 5 │