noCatchAssign

Diagnostic Category: lint/suspicious/noCatchAssign

JavaScript (and super languages)

Since: v1.0.0

Sources:

Same as: no-ex-assign

Description

Disallow reassigning exceptions in catch clauses.

Assignment to a catch parameter can be misleading and confusing. It is often unintended and indicative of a programmer error.

Examples

Invalid

try {

} catch (e) {
  e;
  e = 10;
}

code-block.js:5:3 lint/suspicious/noCatchAssign ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Reassigning a catch parameter is confusing.
  
    3 │ } catch (e) {
    4 │   e;
  > 5 │   e = 10;
      │   ^
    6 │ }
    7 │ 
  
  ℹ The catch parameter is declared here:
  
    1 │ try {
    2 │ 
  > 3 │ } catch (e) {
      │          ^
    4 │   e;
    5 │   e = 10;
  
  ℹ Use a local variable instead.

Valid

try {

} catch (e) {
  let e = 10;
  e = 100;
}

How to configure

{
  "linter": {
    "rules": {
      "suspicious": {
        "noCatchAssign": "error"
      }
    }
  }
}