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typescript/parameter-properties Style

What it does

Requires or disallows parameter properties in class constructors.

Why is this bad?

Mixing parameter properties and class property declarations can make class style inconsistent and harder to maintain.

Examples

{ "prefer": "class-property" } (default)

Examples of incorrect code for this rule:

class Foo {
  constructor(private name: string) {}
}

Examples of correct code for this rule:

class Foo {
  name: string;
  constructor(name: string) {
    this.name = name;
  }
}

{ "prefer": "parameter-property" }

Examples of incorrect code for this rule:

class Foo {
  name: string;
  constructor(name: string) {
    this.name = name;
  }
}

Examples of correct code for this rule:

class Foo {
  constructor(private name: string) {}
}

Configuration

This rule accepts a configuration object with the following properties:

allow

type: array

default: []

Modifiers that are allowed to be used with parameter properties or class properties, depending on the prefer option.

allow[n]

type: "private" | "private readonly" | "protected" | "protected readonly" | "public" | "public readonly" | "readonly"

prefer

type: "class-property" | "parameter-property"

default: "class-property"

Whether to prefer parameter properties or class properties.

How to use

To enable this rule using the config file or in the CLI, you can use:

Config (.oxlintrc.json)

{
  "rules": {
    "typescript/parameter-properties": "error"
  }
}

CLI

oxlint --deny typescript/parameter-properties

References

• Rule Source