noUselessConstructor

JavaScript (and super languages)

摘要

¥Summary

规则生效日期：v1.0.0

¥Rule available since: v1.0.0
诊断类别：lint/complexity/noUselessConstructor

¥Diagnostic Category: lint/complexity/noUselessConstructor
此规则为推荐规则，默认启用。

¥This rule is recommended, which means is enabled by default.
此规则包含 unsafe 修复程序。

¥This rule has an unsafe fix.
此规则的默认严重级别为 information。

¥The default severity of this rule is information.
来源：

¥Sources:
- 与 no-useless-constructor 相同
  
  ¥Same as no-useless-constructor
- 与 @typescript-eslint/no-useless-constructor 相同
  
  ¥Same as @typescript-eslint/no-useless-constructor

如何配置

¥How to configure

1
{
2
  "linter": {
3
    "rules": {
4
      "complexity": {
5
        "noUselessConstructor": "error"
6
      }
7
    }
8
  }
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}

描述

¥Description

禁止不必要的构造函数。

¥Disallow unnecessary constructors.

如果未指定，ES2015 提供默认类构造函数。因此，提供空构造函数或委托给其父级的构造函数是不必要的。

¥ES2015 provides a default class constructor if one is not specified. As such, providing an empty constructor or one that delegates into its parent is unnecessary.

规则忽略：

¥The rule ignores:

装饰类；

¥decorated classes;
至少有一个参数属性的构造函数；

¥constructors with at least one parameter property;
private 和 protected 构造函数。

¥private and protected constructors.

注意事项

¥Caveat

此规则报告唯一目的是使父构造函数公开的构造函数。参见最后一个无效示例。

¥This rule reports on constructors whose sole purpose is to make a parent constructor public. See the last invalid example.

示例

¥Examples

无效

¥Invalid

1
class A {
2
    constructor (a) {}
3
}

code-block.js:2:5 lint/complexity/noUselessConstructor  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ This constructor is unnecessary.
  
    1 │ class A {
  > 2 │     constructor (a) {}
      │     ^^^^^^^^^^^^^^^^^^
    3 │ }
    4 │ 
  
  ℹ Unsafe fix: Remove the unnecessary constructor.
  
    1 1 │   class A {
    2   │ - ····constructor·(a)·{}
    3 2 │   }
    4 3 │

1
class B extends A {
2
    constructor (a) {
3
        super(a);
4
    }
5
}

code-block.ts:2:5 lint/complexity/noUselessConstructor  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ This constructor is unnecessary.
  
    1 │ class B extends A {
  > 2 │     constructor (a) {
      │     ^^^^^^^^^^^^^^^^^
  > 3 │         super(a);
  > 4 │     }
      │     ^
    5 │ }
    6 │ 
  
  ℹ Unsafe fix: Remove the unnecessary constructor.
  
    1 1 │   class B extends A {
    2   │ - ····constructor·(a)·{
    3   │ - ········super(a);
    4   │ - ····}
    5 2 │   }
    6 3 │

1
class C {
2
    /**
3

4
     * Documented constructor.
5
     */
6
    constructor () {}
7
}

code-block.js:5:5 lint/complexity/noUselessConstructor  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ This constructor is unnecessary.
  
    3 │      * Documented constructor.
    4 │      */
  > 5 │     constructor () {}
      │     ^^^^^^^^^^^^^^^^^
    6 │ }
    7 │ 
  
  ℹ Unsafe fix: Remove the unnecessary constructor.
  
    1 1 │   class C {
    2   │ - ····/**
    3   │ - ·····*·Documented·constructor.
    4   │ - ·····*/
    5   │ - ····constructor·()·{}
    6 2 │   }
    7 3 │

1
class A {
2
    protected constructor() {
3
        this.prop = 1;
4
    }
5
}
6

7
class B extends A {
8
    // Make the parent constructor public.
9
    constructor () {
10
        super();
11
    }
12
}

code-block.ts:9:5 lint/complexity/noUselessConstructor  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ This constructor is unnecessary.
  
     7 │ class B extends A {
     8 │     // Make the parent constructor public.
   > 9 │     constructor () {
       │     ^^^^^^^^^^^^^^^^
  > 10 │         super();
  > 11 │     }
       │     ^
    12 │ }
    13 │ 
  
  ℹ Unsafe fix: Remove the unnecessary constructor.
  
     6 6 │   
     7 7 │   class B extends A {
     8   │ - ····//·Make·the·parent·constructor·public.
     9   │ - ····constructor·()·{
    10   │ - ········super();
    11   │ - ····}
    12 8 │   }
    13 9 │

有效

¥Valid

1
class A {
2
    constructor (prop) {
3
        this.prop = prop;
4
    }
5
}

1
class B extends A {
2
    constructor () {
3
        super(5);
4
    }
5
}

1
class C {
2
    // Empty constructor with parameter properties are allowed.
3
    constructor (private prop: number) {}
4
}

1
class D {
2
  constructor(public arg: number){}
3
}
4

5
class F extends D {
6
  // constructor with default parameters are allowed.
7
  constructor(arg = 4) {
8
    super(arg)
9
  }
10
}

1
@Decorator
2
class C {
3
    constructor (prop: number) {}
4
}

noUselessConstructor

摘要

如何配置

描述

注意事项

示例

无效

有效

相关链接