noUselessEscapeInString (JavaScript)

Summary

Rule available since: v2.0.0
Diagnostic Category: lint/suspicious/noUselessEscapeInString
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
        "noUselessEscapeInString": "error"
6
      }
7
    }
8
  }
9
}

Description

Disallow unnecessary escapes in string literals.

Escaping non-special characters in string literals doesn’t have any effect. Hence, they may confuse a reader.

Examples

Invalid

1
const s = "\a";

code-block.js:1:13 lint/suspicious/noUselessEscapeInString  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ The character doesn't need to be escaped.
  
  > 1 │ const s = "\a";
      │             ^
    2 │ 
  
  ℹ Only quotes that enclose the string and special characters need to be escaped.
  
  ℹ Safe fix: Unescape the character.
  
    1 │ const·s·=·"\a";
      │            -

1
const o = {
2
    "\a": 0,
3
};

code-block.js:2:7 lint/suspicious/noUselessEscapeInString  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ The character doesn't need to be escaped.
  
    1 │ const o = {
  > 2 │     "\a": 0,
      │       ^
    3 │ };
    4 │ 
  
  ℹ Only quotes that enclose the string and special characters need to be escaped.
  
  ℹ Safe fix: Unescape the character.
  
    2 │ ····"\a":·0,
      │      -

1
const s = `${0}\a`;

code-block.js:1:17 lint/suspicious/noUselessEscapeInString  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ The character doesn't need to be escaped.
  
  > 1 │ const s = `${0}\a`;
      │                 ^
    2 │ 
  
  ℹ Only quotes that enclose the string and special characters need to be escaped.
  
  ℹ Safe fix: Unescape the character.
  
    1 │ const·s·=·`${0}\a`;
      │                -

Valid

1
const s = "\n";

In template literals, \${ and $\{ are valid escapes:

1
const s = `\${0}`;

Tagged string templates are ignored:

1
const s = tagged`\a`;

JSX strings are ignored:

1
<div attr="str\a"/>;