useConsistentBuiltinInstantiation (since v1.7.2)

Diagnostic Category: lint/nursery/useConsistentBuiltinInstantiation

Sources:

Same as: unicorn/new-for-builtins
Same as: no-new-wrappers

Enforce the use of new for all builtins, except String, Number, Boolean, Symbol and BigInt.

new Builtin() and Builtin() work the same, but new should be preferred for consistency with other constructors. Enforces the use of new for following builtins:

AggregateError
Array
ArrayBuffer
BigInt64Array
BigUint64Array
DataView
Date
Error
EvalError
FinalizationRegistry
Float32Array
Float64Array
Function
Int16Array
Int32Array
Int8Array
Map
Object
Promise
Proxy
RangeError
ReferenceError
RegExp
Set
SharedArrayBuffer
SyntaxError
TypeError
URIError
Uint16Array
Uint32Array
Uint8Array
Uint8ClampedArray
WeakMap
WeakRef
WeakSet

Disallows the use of new for following builtins:

BigInt
Boolean
Number
String
Symbol

These should not use new as that would create object wrappers for the primitive values, which is not what you want. However, without new they can be useful for coercing a value to that type.

Examples

Invalid

const text = new String(10);

code-block.js:1:14 lint/nursery/useConsistentBuiltinInstantiation  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Use String() instead of new String().
  
  > 1 │ const text = new String(10);
      │              ^^^^^^^^^^^^^^
    2 │ 
  
  ℹ Unsafe fix: Remove new keyword.
  
    1 │ const·text·=·new·String(10);
      │              ----

const now = Date();

code-block.js:1:13 lint/nursery/useConsistentBuiltinInstantiation  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Use new Date() instead of Date().
  
  > 1 │ const now = Date();
      │             ^^^^^^
    2 │ 
  
  ℹ Unsafe fix: Add new keyword.
  
    1 │ const·now·=·new·Date();
      │             ++++

const map = Map([
  ['foo', 'bar']
]);

code-block.js:1:13 lint/nursery/useConsistentBuiltinInstantiation  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ Use new Map() instead of Map().
  
  > 1 │ const map = Map([
      │             ^^^^^
  > 2 │   ['foo', 'bar']
  > 3 │ ]);
      │ ^^
    4 │ 
  
  ℹ Unsafe fix: Add new keyword.
  
    1 │ const·map·=·new·Map([
      │             ++++

Valid

const text = String(10);

const now = new Date();

const map = new Map([
 ['foo', 'bar']
]);