noUselessCatch

JavaScript (and super languages)

Summary

Rule available since: v1.0.0
Diagnostic Category: lint/complexity/noUselessCatch
This rule is recommended, which means is enabled by default.
This rule has an unsafe fix.
The default severity of this rule is information.
Sources:
- Same as no-useless-catch

Description

Disallow unnecessary catch clauses.

A catch clause that only rethrows the original error is redundant, and has no effect on the runtime behavior of the program. These redundant clauses can be a source of confusion and code bloat, so it’s better to disallow these unnecessary catch clauses.

Examples

Invalid

1
try {
2
    doSomething();
3
} catch(e) {
4
    throw e;
5
}

code-block.js:4:5 lint/complexity/noUselessCatch ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ The catch clause that only rethrows the original error is useless.
  
    2 │     doSomething();
    3 │ } catch(e) {
  > 4 │     throw e;
      │     ^^^^^^^^
    5 │ }
    6 │ 
  
  ℹ An unnecessary catch clause can be confusing.

1
try {
2
    doSomething();
3
} catch(e) {
4
    throw e;
5
} finally {
6
    doCleanUp();
7
}

code-block.js:4:5 lint/complexity/noUselessCatch  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ℹ The catch clause that only rethrows the original error is useless.
  
    2 │     doSomething();
    3 │ } catch(e) {
  > 4 │     throw e;
      │     ^^^^^^^^
    5 │ } finally {
    6 │     doCleanUp();
  
  ℹ An unnecessary catch clause can be confusing.
  
  ℹ Unsafe fix: Remove the catch clause.
  
    1 1 │   try {
    2 2 │       doSomething();
    3   │ - }·catch(e)·{
    4   │ - ····throw·e;
    5   │ - }·finally·{
      3 │ + }·finally·{
    6 4 │       doCleanUp();
    7 5 │   }

Valid

1
try {
2
    doSomething();
3
} catch(e) {
4
    doSomethingWhenCatch();
5
    throw e;
6
}

1
try {
2
    doSomething();
3
} catch(e) {
4
    handleError(e);
5
}

1
try {
2
    doSomething();
3
} finally {
4
    doCleanUp();
5
}

How to configure

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