# Reassigning object methods is not supported Rule ``arkts-no-method-reassignment`` **Severity: error** ArkTS does not support re-assigning a method for objects. In the statically types languages, the layout of objects is fixed and all instances of the same object must share the same code of each method. If you need to add specific behavior for certain objects, you can create separate wrapper functions or use inheritance. ## TypeScript ``` class C { foo() { console.log("foo") } } function bar() { console.log("bar") } let c1 = new C() let c2 = new C() c2.foo = bar c1.foo() // foo c2.foo() // bar ``` ## ArkTS ``` class C { foo() { console.log("foo") } } class Derived extends C { foo() { console.log("Extra") super.foo() } } function bar() { console.log("bar") } let c1 = new C() let c2 = new C() c1.foo() // foo c2.foo() // foo let c3 = new Derived() c3.foo() // Extra foo ```