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    internal class 使用非同步製作Pizza: 使用同步製作Pizza
    {
        private static int Pizza總數 = 0;
        private static object tsLock = new object();

        internal void 開始()
        {
            var watch = Stopwatch.StartNew();
            Console.WriteLine("開始進行製作披薩...");

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Angular 8 開發環境說明

• 為了能讓大家能夠順利的建立起 Angular 8 開發環境，以下是需要安裝的相關軟體與安裝步驟與說明。

[ 作業系統 ]

• Windows 7 以上版本 (更新到最新 Service Pack 版本)
• Mac OS X 10.6 以上版本

[ 套件管理器 ( Mac OS X Only ) ]

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New in Chrome 80  |  Web  |  Google Developers
https://developers.google.com/web/updates/2020/02/nic80?fbclid=IwAR2nKXVG8kxLpJ2kgwVbLqYiAbEIXvGUMkeiuKFcQczVhgbHJoo470RyFww#opt-chaining

var ABC = function(){this.a = '123'}
ABC.prototype._fun1 = function(){return this.a.length}
ABC.prototype._fun2 = function(){return this.b?.length}
var abc = new ABC();

abc._fun1() // 3

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<!-- *ngIf, else, ng-container 與 ng-template 搭配使用 -->
<span class="highlight">
    <ng-container *ngIf="keyword === ''; then pleaseInput; else yourInput"></ng-container>
    <ng-template #pleaseInput>
        請輸入關鍵字
    </ng-template>
    <ng-template #yourInput>
        你輸入: {{ keyword }}
    </ng-template>
</span>

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//Creation Operator - from 輸入陣列 or 字串 or Promise 物件

var arr = ['Jerry', 'Anna', 2016, 2017, '30 days'] 
var source = Rx.Observable.from(arr);

source.subscribe({
    next: function(value) {
        console.log(value)
    },
    complete: function() {

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// Operators - combineLatest  
/*
同時執行多個 observable 實例，
且湊齊所有的 next 才會執行 Callack Function
每湊齊一次，執行一次 Callack Function
其中一個 observable 只要一有值，就會保留(延續)，直到被自己覆蓋。

適合用在多 observable，只會變動其中一個 observable，但又要湊齊變數。
*/
var source = Rx.Observable.interval(500).take(3);

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// Operators - zip
var source = Rx.Observable.interval(500).take(3);
var newest = Rx.Observable.interval(300).take(6);

var example = source.zip(newest, (x, y) => x + y);

example.subscribe({
    next: (value) => { console.log(value); },
    error: (err) => { console.log('Error: ' + err); },
    complete: () => { console.log('complete'); }

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// Operators - withLatestFrom
var main = Rx.Observable.from([1,2,3,4,5]).zip(Rx.Observable.interval(500), (x, y) => x);
var some = Rx.Observable.from([0,1,0,0,0,1]).zip(Rx.Observable.interval(300), (x, y) => x);

var example = main.withLatestFrom(some, (x, y) => {
    return y === 1 ? x*10 : x;
});

example.subscribe({
    next: (value) => { console.log(value); },

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//1. 正常 情況
var people = [
    {name: 'Anna', score: 100, subject: 'English'},
    {name: 'Anna', score: 90, subject: 'Math'},
    {name: 'Anna', score: 96, subject: 'Chinese' }, 
    {name: 'Jerry', score: 80, subject: 'English'},
    {name: 'Jerry', score: 100, subject: 'Math'},
    {name: 'Jerry', score: 90, subject: 'Chinese' }, 
];
var source = Rx.Observable

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```sql
SELECT name AS [Database Name],
recovery_model_desc AS [Recovery Model] FROM sys.databases
GO
```

![](https://cdn.cacher.io/attachments/u/3bjrfdy09ammu/Ou04mhY5rHJqiFDmgKIX81Dfab70nKCM/yy9s57d5s.png)