useThrowNewError (since v1.8.0)

Diagnostic Category: lint/nursery/useThrowNewError

Sources:

Same as: unicorn/throw-new-error

Require new when throwing an error.

While it’s possible to instantiate Error without using the new keyword, it’s better to be consistent: modern builtins require new to be instantiated.

Rule matches errors when their name ends with the word “Error” and the first character is uppercase.

Examples

Invalid

throw Error();

code-block.js:1:7 lint/nursery/useThrowNewError  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Use new Error() instead of Error() when throwing an error.
  
  > 1 │ throw Error();
      │       ^^^^^^^
    2 │ 
  
  ℹ Instantiate Error with new keyword for consistency with modern builtins.
  
  ℹ Unsafe fix: Add new keyword.
  
    1 │ throw·new·Error();
      │       ++++

throw TypeError('biome');

code-block.js:1:7 lint/nursery/useThrowNewError  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Use new TypeError() instead of TypeError() when throwing an error.
  
  > 1 │ throw TypeError('biome');
      │       ^^^^^^^^^^^^^^^^^^
    2 │ 
  
  ℹ Instantiate Error with new keyword for consistency with modern builtins.
  
  ℹ Unsafe fix: Add new keyword.
  
    1 │ throw·new·TypeError('biome');
      │       ++++

throw lib.TypeError();

code-block.js:1:7 lint/nursery/useThrowNewError  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Use new TypeError() instead of TypeError() when throwing an error.
  
  > 1 │ throw lib.TypeError();
      │       ^^^^^^^^^^^^^^^
    2 │ 
  
  ℹ Instantiate Error with new keyword for consistency with modern builtins.
  
  ℹ Unsafe fix: Add new keyword.
  
    1 │ throw·new·lib.TypeError();
      │       ++++

Valid

throw new Error();

throw new TypeError('biome');

throw new lib.TypeError();