使用@HostListener挂钩,但确认对话框(询问:你想离开这个页面?...还是你想重新加载这个页面?)没有显示.
代码有效,但确认对话框未显示.
在这里我有:
@HostListener('window:beforeunload', ['$event'])
public doSomething($event) {
console.log("do I see this?") // <---- this logs to the console.
return "something else";
}
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但我没有看到这个:
share()运算符应用于BehaviorSubject.BehaviorSubject具有初始值.
目标是创建单个共享订阅.但是,当BehaviorSubject具有初始值时,此共享订阅似乎不起作用.
获得意外结果.
代码如下所示:
let subject = new Rx.BehaviorSubject(0);
let published = subject
.do(v => console.log("side effect"))
.share();
published.subscribe((v) => console.log(v+" sub1"));
published.subscribe((v) => console.log(v+" sub2"));
subject.next(1);
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结果:
"side effect"
"0 sub1"
"side effect"
"1 sub1"
"1 sub2"
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预期结果:
"side effect"
"0 sub1"
"1 sub1" <------------- this is missing from actual result
"side effect"
"1 sub1"
"1 sub2"
Run Code Online (Sandbox Code Playgroud) std::chrono:ceilc++ 17 之前的 c++ 版本是否有替代方案?
我想将 time_point 舍入到它的分钟上限(即最近的分钟)。
https://en.cppreference.com/w/cpp/chrono/duration/ceil
std::chrono::time_point<std::chrono::system_clock> time_point_now = std::chrono::system_clock::now();
auto start_time = std::chrono::ceil<std::chrono::minutes>(time_point_now);
...
Run Code Online (Sandbox Code Playgroud) 在下面的typings.json文件中,ambientDependencies(或globalDependencies)和常规依赖项之间的区别是什么:
{
"ambientDependencies": {
"es6-shim": "registry:dt/es6-shim#0.31.2+20160317120654",
"jasmine": "registry:dt/jasmine#2.2.0+20160412134438",
"jquery": "registry:dt/jquery#1.10.0+20160417213236"
},
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"依赖":{},<---这是做什么的?
}
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typings install <something> --save 将保存为依赖项,但这意味着什么?
尝试grunt.loadNpmTasks('grunt-express-server');从外部目录加载模块:
得到一个错误:任务....不存在.你装了吗?
目录结构:
client/
node_modules
gruntfile
dev_server/
node_modules/
grunt-express-server
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所以我的问题是:如何使用存储在外部目录中的节点模块运行grunt-task?
选中复选框时查看不更新.我应该使用$ scope.$ apply?我需要Current state在YES和NO之间切换,具体取决于是否选中了复选框.这是 JSbin 上的代码
<!DOCTYPE html>
<html ng-app="notesApp">
<head>
<title>Notes App</title></head>
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.3.8/angular.js"></script>
<body ng-controller="MainCtrl as ctrl">
<div>
<h2>What are your favorite sports?</h2>
<div ng-repeat="sport in ctrl.sports">
<br/>
<label ng-bind="sport.label"></label>
<div>
<input type="checkbox"
ng-model="sport.selected"
ng-true-value="YES"
ng-false-value="NO">
</div>
<div>
Current state: {{sport.selected}}
</div>
</div>
</div>
</body>
</html>
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这是JS:
angular.module('notesApp', [])
.controller('MainCtrl', [function() {
var self = this;
self.sports = [
{label: 'Basketball', selected: 'YES'},
{label: 'Cricket', selected: 'NO'},
{label: 'Soccer', selected: 'NO'},
{label: 'Swimming', selected: …Run Code Online (Sandbox Code Playgroud) 我正在使用正则表达式来验证JavaScript中的电子邮件地址.
正则表达式非常简单.它检查三件事:1)'@',2)'.' ('dot'在something@gmail.com中),以及3)电子邮件地址中的'az'.如果所有三个都返回true,则电子邮件地址有效(根据我的验证,至少)
这是代码:
function checkemail(){
var e = document.getElementById("email").value;
if((e.match(/@/g)==null)||(e.match(/[a-z]/ig)==null)||(e.match(/./g)==null)){
//display error message
}
}
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我的问题是:
(e.match(/./g)==null); //returns false even though there are no dots in the string e
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即使字符串中没有点,也会返回false.
例如:
("thisIsMyEmail".match(/./ig))==null //returns false
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如果它应该是真的,为什么它会返回false?
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