noRedundantUseStrict

Цей контент ще не доступний вашою мовою.

JavaScript (and super languages)

Summary

Rule available since: v1.0.0
Diagnostic Category: lint/suspicious/noRedundantUseStrict
This rule is recommended, meaning it is enabled by default.
This rule has a safe fix.
The default severity of this rule is warning.

How to configure

1
{
2
  "linter": {
3
    "rules": {
4
      "suspicious": {
5
        "noRedundantUseStrict": "error"
6
      }
7
    }
8
  }
9
}

Description

Prevents from having redundant "use strict".

The directive "use strict" isn’t needed in .mjs files, or in .js files inside projects where the package.json defines library as module:

1
{
2
   "type": "module"
3
}

Instead, .cjs files are considered “scripts” and the directive "use strict" is accepted and advised.

Examples

Invalid

1
"use strict";
2
function foo() {
3
   "use strict";
4
}

code-block.cjs:3:3 lint/suspicious/noRedundantUseStrict  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Redundant use strict directive.
  
    1 │ “use strict”;
    2 │ function foo() {
  > 3 │  	“use strict”;
      │  	^^^^^^^^^^^^^
    4 │ }
    5 │ 
  
  ℹ This outer use strict directive already enables strict mode.
  
  > 1 │ “use strict”;
      │ ^^^^^^^^^^^^^
    2 │ function foo() {
    3 │  	“use strict”;
  
  ℹ Safe fix: Remove the redundant use strict directive.
  
    1 1 │   “use strict”;
    2 2 │   function foo() {
    3   │ - ·→ “use·strict”;
      3 │ + ·→ 
    4 4 │   }
    5 5 │

1
"use strict";
2
"use strict";
3

4
function foo() {
5

6
}

code-block.cjs:2:1 lint/suspicious/noRedundantUseStrict  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Redundant use strict directive.
  
    1 │ “use strict”;
  > 2 │ “use strict”;
      │ ^^^^^^^^^^^^^
    3 │ 
    4 │ function foo() {
  
  ℹ This outer use strict directive already enables strict mode.
  
  > 1 │ “use strict”;
      │ ^^^^^^^^^^^^^
    2 │ “use strict”;
    3 │ 
  
  ℹ Safe fix: Remove the redundant use strict directive.
  
    1 1 │   “use strict”;
    2   │ - “use·strict”;
    3 2 │   
      3 │ + 
    4 4 │   function foo() {
    5 5 │

1
function foo() {
2
"use strict";
3
"use strict";
4
}

code-block.cjs:3:1 lint/suspicious/noRedundantUseStrict  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Redundant use strict directive.
  
    1 │ function foo() {
    2 │ “use strict”;
  > 3 │ “use strict”;
      │ ^^^^^^^^^^^^^
    4 │ }
    5 │ 
  
  ℹ This outer use strict directive already enables strict mode.
  
    1 │ function foo() {
  > 2 │ “use strict”;
      │ ^^^^^^^^^^^^^
    3 │ “use strict”;
    4 │ }
  
  ℹ Safe fix: Remove the redundant use strict directive.
  
    1 1 │   function foo() {
    2 2 │   “use strict”;
    3   │ - “use·strict”;
      3 │ + 
    4 4 │   }
    5 5 │

1
class C1 {
2
  test() {
3
    "use strict";
4
  }
5
}

code-block.cjs:3:3 lint/suspicious/noRedundantUseStrict  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Redundant use strict directive.
  
    1 │ class C1 {
    2 │ 	test() {
  > 3 │ 		“use strict”;
      │ 		^^^^^^^^^^^^^
    4 │ 	}
    5 │ }
  
  ℹ All parts of a class’s body are already in strict mode.
  
  > 1 │ class C1 {
      │ ^^^^^^^^^^
  > 2 │ 	test() {
  > 3 │ 		“use strict”;
  > 4 │ 	}
  > 5 │ }
      │ ^
    6 │ 
  
  ℹ Safe fix: Remove the redundant use strict directive.
  
    1 1 │   class C1 {
    2 2 │   	test() {
    3   │ - → → “use·strict”;
    4   │ - → }
      3 │ + → → 
      4 │ + → }
    5 5 │   }
    6 6 │

1
const C2 = class {
2
  test() {
3
    "use strict";
4
  }
5
};

code-block.cjs:3:3 lint/suspicious/noRedundantUseStrict  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Redundant use strict directive.
  
    1 │ const C2 = class {
    2 │ 	test() {
  > 3 │ 		“use strict”;
      │ 		^^^^^^^^^^^^^
    4 │ 	}
    5 │ };
  
  ℹ All parts of a class’s body are already in strict mode.
  
  > 1 │ const C2 = class {
      │            ^^^^^^^
  > 2 │ 	test() {
  > 3 │ 		“use strict”;
  > 4 │ 	}
  > 5 │ };
      │ ^
    6 │ 
  
  ℹ Safe fix: Remove the redundant use strict directive.
  
    1 1 │   const C2 = class {
    2 2 │   	test() {
    3   │ - → → “use·strict”;
    4   │ - → }
      3 │ + → → 
      4 │ + → }
    5 5 │   };
    6 6 │

Valid

1
function foo() {
2

3
}

1
 function foo() {
2
    "use strict";
3
}
4
function bar() {
5
    "use strict";
6
}