In Angular2, sometime we use @Output to pass data to parent component, then parent may pass the data down to another child component. When you want to display the property of this object, we may need to check whether the object exists or not, otherwi…

function addTo80(n ) { + n; } function memoizedAddTo80 (fn) { let cache = {}; return (n) => { /*keyword 'in' to check prop exists*/ if (n in cache) { console.log('from cache') return cache[n] } else { console.log('from calculation') cache[n] = fn(n)…

windows下载安装完最新版本的Scala(2.12.4)后,终端如下错误 C:\Users\Administrator>scala -versionException in thread "main" java.lang.VerifyError: Uninitialized object exists on backward branch 96Exception Details: Location: scala/tools/nsc/CompilerCommand.sstrin…

网上下载了一个demo,编译出现如下错误: Gradle sync failed: Uninitialized object exists on backward branch 70 Exception Details: Location: com/android/build/gradle/tasks/BuildArtifactReportTask.newArtifact(Lcom/android/build/api/artifact/BuildableArtifact;)Lcom/androi…

时间:2014年12月15日 14:15:10 /** * @license AngularJS v1.3.0-beta.15 * (c) 2010-2014 Google, Inc. http://angularjs.org * License: MIT */ (function(window, document, undefined) {'use strict'; /** * @description * * This object provides a utility for produc…

angular的工具函数 在angular的API文档中,在最前面就是讲的就是angular的工具函数,下面列出来 angular.bind //用户将函数和对象绑定在一起,返回一个新的函数 angular.bootstrap //angular启动函数,一般不用,除了e2e测试 angular.copy //对象拷贝 angular.element //jQlite,作用类似于jQuery angular.equals //对象比较.用 == 对两个对象进行比较,除非他们是同一个对象的引用,否…

In this lesson, we’ll use a Maybe to safely operate on properties of an object that could be undefined. We’ll use our initial code as the basis for a prop utility function that can be reused with different objects and various property names. Instead…

原文链接:https://www.javaspring.net/java/what-happened-when-new-an-object-in-jvm I. Introduction As you know, Java is an object-oriented programming language. We usually use a variety of objects while writing code. So when you write User user = new User(…

Angular CLI 1.7.4 在使用 ng build --prod 会构建失败,而 ng build 是正常的.比较好的解决办法是使用 ng build --prod --extract-licenses=false 或者 ng build --prod --no-extract-licenses. 最近将 Angular CLI 升级到 6.X 之后,直接 ng build 会报以下错误,ng serve 也是如此. 95% emitting LicenseWebpackPlugin(…

转 https://willweissman.wordpress.com/tutorials/shaders/unity-shaderlab-object-outlines/ Unity Shaderlab: Object Outlines One of the simplest and most useful effects that isn’t already present in Unity is object outlines. Screenshot from Left 4 Dead.…