topic description A method under the constructor (non-static method) does not want to execute the constructed method related codes Please paste the code text below (do not replace the code with pictures) class website extend site { ...
learn the constructor and encounter the following code when doing exercises the code is as follows function Fn(){ return this; } Fn.prototype.getNum = function(){ console.log(3); }; new new Fn().getNum (); Why is the output 3? what I under...
I have a base class, Base.php, that initializes the constructor. public function __construct() { parent::__construct(); $this->authWen(); } The constructor calls a permission verification method. However, in addition to true...
I encountered some confusion when learning the prototype chain as follows: in some blogs (such as Ruan Yifeng s blog), it is said: JavaScript natively provides Object objects, and all other objects inherit from Object objects, that is, those o...
JavaScript Advanced programming (3rd Edition) P144 the meaning expressed in (2). It s not what I understand. -reference elevation content start- English explanation To create a new instance of Person, use the new operator. Calling a constructor i...
I javascript A novice, recently encountered a problem that I have been unable to understand, as follows: var A = function() { return new B() } var B = function() { this.name = B } var a = A() console.log(Object.getPrototypeOf(a) == B.pro...
CPP11 allows list initialization for all objects, and because the constructor body is assigned, references and const variables must be initialized first, so you must use list initialization, so how is it initialized before CPP11? ...
when referencing popper.js, if packaging does not rule out popper.js, calling new PopperJS, an error will be reported let PopperJS = require( . popper ); let popper = new PopperJS(); PopperJS is not a constructor webpack.base.conf.js: ...
I js novice, recently encountered a little question when learning the content of the object, as follows: personal understanding: every time an instance object is generated using the new command, all the properties in the constructor will be define...
problem description Android cannot be packaged Users XXXXXX XXXXXX android app build intermediates res merged release drawable-xhdpi node_modules_reactnativecalendars_src_calendar_img_previous.png: error: uncompiled PNG file passed as argument. due...
about TypeScript. See the code below. interface MyInterface { } class MyClassA implements MyInterface { } class MyClassB implements MyInterface { } const createMyInterface = (_interface: any) => { return new _interface(); } createMyInterface(M...
I now use the method of overlaying the map and the scatter map to put the scatter map on the corresponding map, but the function I want to achieve is: when the mouse moves into the map area of a certain province, when the area gets the focus, the area d...
EventLoop mechanism: macro task this macro task queue is maintained by event-triggered threads. ask God to inform micro task whether this micro-task queue is maintained by event-triggered threads or by JS engine threads ? ...
No matter what password you set, it doesn t work. You can enter any password when you log in. View and display in mysql as follows: < table > < thead > < tr > < th > MariaDB [mysql] > select authentication_string from user; < th > < tr > < thea...