new Operatorsuper Keyword? : ), )if Statementdo-while Statementwhile Statementfor Statementfor-in,for-of, andfor-await-of Statementscontinue Statementbreak Statementreturn Statementwith Statementswitch Statementthrow Statementtry Statementdebugger Statement?um/p1-90`A
TheWeakRef
extends clause of a class definition. SubclassWeakRef behaviour must include asuper call to theWeakRefWeakRef.prototype built-in methods.This function performs the following steps when called:
The initial value ofWeakRef.prototype is the
This property has the attributes {[[Writable]]:
TheWeakRef prototype object:
The initial value ofWeakRef.prototype.constructor is
This method performs the following steps when called:
If the
let target = {foo() {} };let weakRef =newWeakRef(target);// ... later ...if (weakRef.deref()) { weakRef.deref().foo();}In the above example, if the first deref does not evaluate to
The initial value of the
This property has the attributes {[[Writable]]:
The abstract operation WeakRefDeref takes argumentweakRef (a
This abstract operation is defined separately from WeakRef.prototype.deref strictly to make it possible to succinctly define liveness.
A
TheFinalizationRegistry
extends clause of a class definition. SubclassFinalizationRegistry behaviour must include asuper call to theFinalizationRegistryFinalizationRegistry.prototype built-in methods.This function performs the following steps when called:
The
The initial value ofFinalizationRegistry.prototype is the
This property has the attributes {[[Writable]]:
TheFinalizationRegistry prototype object:
The initial value ofFinalizationRegistry.prototype.constructor is
This method performs the following steps when called:
Based on the algorithms and definitions in this specification,cell.[[HeldValue]] is
This method performs the following steps when called:
The initial value of the
This property has the attributes {[[Writable]]: