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No Obj Calls

lint/rules/no-obj-calls.md

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Disallows calling built-in global objects like functions.

The following built-in objects should not be invoked like functions, even though they look like constructors:

  • Math
  • JSON
  • Reflect
  • Atomics

Calling these as functions would result in runtime errors. This rule statically prevents such wrong usage of them.

Invalid:

typescript
const math = Math();
const newMath = new Math();

const json = JSON();
const newJSON = new JSON();

const reflect = Reflect();
const newReflect = new Reflect();

const atomics = Atomics();
const newAtomics = new Atomics();

Valid:

typescript
const area = (radius: number): number => Math.PI * radius * radius;

const parsed = JSON.parse("{ foo: 42 }");

const x = Reflect.get({ x: 1, y: 2 }, "x");

const first = Atomics.load(foo, 0);