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noUselessCatch (since v1.0.0)

Diagnostic Category: lint/complexity/noUselessCatch

Sources:

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

Section titled Examples

Invalid

Section titled Invalid
try {
    doSomething();
} catch(e) {
    throw e;
}
complexity/noUselessCatch.js:4:5 lint/complexity/noUselessCatch ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ The catch clause that only rethrows the original error is redundant.
  
    2 │     doSomething();
    3 │ } catch(e) {
  > 4 │     throw e;
      │     ^^^^^^^^
    5 │ }
    6 │ 
  
  ℹ These unnecessary catch clauses can be confusing. It is recommended to remove them.
  

try {
    doSomething();
} catch(e) {
    throw e;
} finally {
    doCleanUp();
}
complexity/noUselessCatch.js:4:5 lint/complexity/noUselessCatch ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ The catch clause that only rethrows the original error is redundant.
  
    2 │     doSomething();
    3 │ } catch(e) {
  > 4 │     throw e;
      │     ^^^^^^^^
    5 │ } finally {
    6 │     doCleanUp();
  
  ℹ These unnecessary catch clauses can be confusing. It is recommended to remove them.

Valid

Section titled Valid
try {
    doSomething();
} catch(e) {
    doSomethingWhenCatch();
    throw e;
}
try {
    doSomething();
} catch(e) {
    handleError(e);
}
Section titled Related links