![]() ![]() Other downlevel compilers generally have the same limitation by default. However, there is no way to ensure a value for new.target when invoking a constructor in ECMAScript 5. Developers can use this feature to throw an exception in a constructor without risking the escape of a partially initialized object (via the finalizer attack. ![]() This is due to the fact that constructor functions for Error, Array, and the like use ECMAScript 6’s new.target to adjust the prototype chain Yes you can, your class declaration has an implicit primary constructor. But the meaning of the program hasnt changed: if the Tester class checkRange method throws an exception, it will abort the constructor too, along with the. It is necessary for generated constructor code to capture any potential return value of super(.) and replace it with this.Īs a result, subclassing Error, Array, and others may no longer work as expected. In ES2015, constructors which return an object implicitly substitute the value of this for any callers of super(.). or your compilation target is explicitly set to ES6/ ES2015 or above, you may skip this section Note: If you don’t plan to inherit from built-in types like Array, Error, Map, etc. This means that the base class constructor saw its own value for name during its own constructor, because the derived class field initializations hadn’t run yet. The derived class fields are initialized As you can see from the code, the InputFile class completely ignores the fact that the FileInputStream constructor can throw an exception.The order of class initialization, as defined by JavaScript, is:
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