promise chaining

2018-1-11 20:25:48 ThursdayScene:Previously wanted to chain call must first new an object, and then $obj->aa ()->bb () ...Now the static method of PHP7 (php7.0.13 php7.2 test pass) can also be chained to call theWriting:A::aa ():: BB ():: CC ();Realize:1 classA2 {3 Public Static $a= 0;4 5 Public Static functionAA ()6 {7Self::$a++;8 returnSelf::class;9 }Ten One Public Static functionBB () A { -Self::$a++; - returnSelf::class; the } - -

throwing another exception without losing the original exception.The following code implements an exception chain up-throws an exception in two ways. Public classNevercaught {Static voidF ()throwsexceptionb{Throw NewEXCEPTIONB ("Exception B"); } Static voidG ()throwsExceptionc {Try{f (); } Catch(exceptionb e) {exceptionc C=NewExceptionc ("Exception a"); //Exception ChainC.initcause (e); //another way to achieve this//throw new Exception ("Exception a", e); ThrowC; } } Pu

Swift Programming Language -- Optional chain (Optional Chaining), swiftoptional Optional Chaining is a process that allows you to request and call attributes, methods, and subscripts, its self-sufficiency is reflected in that the current request or call target may be null (nil ). If the self-determined target has a value, the call will succeed. On the contrary, if the selected target is null (nil), the call

This article is the official HTML5 training course for h5edu institutions, mainly introduces: JavaScript intensive tutorial--jquery-chainingWith JQuery, you can link actions/methods together.Chaining allows us to allow multiple jQuery methods (on the same element) in one statement.JQuery Method LinksUntil now, we have written a jQuery statement one at a time (followed by another).However, there is a technique called link (chaining) that allows us to r

Read the study notes in Chapter 2nd of JavaScript advanced programming (version 6th. The prototype has a problem in the reference type: Function supertype () {} supertype. prototype. color = ['red', 'Blue ', 'green']; var instance1 = new supertype (); instance1.color. push ('black'); var instance2 = new supertype (); console. log (instance2.color ); The prototype attribute of the reference type is shared by all instances. Prototype chaining in the i

") takes this type of call, at this point, this points to the window, in the browser environmentIn addition, look at the implementation of chained calls in Java, C #, basically the same principle, the same is the use of this, however, in Java, C #, this represents the current object, and in JavaScript, this is determined by the runtime, not determined by the definition.Roughly that is, in each method body, return this, method return value type is the current class type, you can implement this fu

varA=function(){ This. foo= ' Bar ';} A.prototype={b:1};varAa=function() {}aa.prototype={c:2 , __proto__:a.prototype};varAaa=function() {}aaa.prototype={c:3,d:4 , __proto__:aa.prototype};console.log (NewA ()); Console.log (NewAA ()); Console.log (NewAAA ());It can be found that the objects produced by new AAA () inherit all the properties of the AA class and Class A.Because IE's __proto__ is uncontrollable, Firefox and Chrome only support it. A type of JavaScript

Chaining Hanging chain jquery

# this are to show what you are to execute a series of commands in one strike.$ clear; CD/; Ls-l; echo "You is in $PWD"; echo "Time to go home"; CD ~;# Use semi colon between command.# There is also command lists, which are for a different logic# # Double ampersand means anding, double pipe means ORING; When using if only when the first command exits 0 (successful), the later command would be proceeded; When using | |, if the first command exits none of zero (not successful), the later command

Public class extends Fruit {} class fruit{ public Fruit (String name) { System.out.println ("Fruit's constructor is Invoked ");} }This piece of code seems to be no problem, after compiling the error isBecause Apple does not explicitly define a construction method, Apple's default construction method is called because Apple is a subclass of fruit, and the first sentence of the Apple implicit constructor executes super (), and then calls the constructor of fruit. However, the fruit c

Implement the promises library of nodejs Based on promise. js, promise. jsnodejs Today, I downloaded promise. js from the GIT source code library and found that the source code is written based on Web Front-end JavaScript and cannot be directly used for nodejs. Fortunately, there are not many codes and they are not very complicated. After analysis and integration

Promise implements lazyman., promise implements lazyman First, please refer to the implementation of setTimeout by netizens: Function _ LazyMan (name) {this. tasks = []; var self = this; var fn = (function (n) {var name = n; return function () {console. log ("Hi! This is "+ name + "! "); Self. next () ;}}) (name); this. tasks. push (fn); setTimeout (function () {self. next () ;}, 0); // start the task in th

Let's say $. Deferred jquery with $. Deferred implements the promise specification, $. What the hell is deferred? Or the old way, print out to see, first have a visual impression: Javascript 12 var def = $. Deferred ();Console . Log (def) ; The output is as follows: $. Deferred () Return an object, we can call it the Deferred object, hanging some familiar methods such as: Done, fail, then, etc. jquery uses this defer

Javascript asynchronous programming code writing specification Promise learning notes, promise learning notes Recently, my work was easy. I remembered the word promise which I used to see before. So I learned it with patience. I. What is Promise? Why is there this? First of all, Pr