相关疑难解决方法(0)

我有以下Ecma-Script-6的代码 template literals

let person = {name: 'John Smith'};   
let tpl = `My name is ${person.name}.`;    
let MyVar="My name is "+ person.name+".";

console.log("template literal= "+tpl);  
console.log("my variable = "+MyVar);

输出如下:

template literal= My name is John Smith.
my variable = My name is John Smith.

这是小提琴.我试着寻找确切的差异但找不到它,我的问题是这两个陈述有什么区别,

  let tpl = `My name is ${person.name}.`;    

和

  let MyVar = "My name is "+ person.name+".";

我已经能够在这里MyVar连接字符串person.name了,那么使用模板文字的场景是什么？

我想使用ngForAngular 2将 Firebase 查询的结果绑定到我的模板。这很容易在下面实现。

成分：

export class FeaturedThreadsComponent { 
    threads: FirebaseListObservable<any[]>;
    qualitySubject: Subject<any>;

    constructor(af: AngularFire) {
        this.qualitySubject = new Subject();
        this.threads = af.database.list('/threads', {
            query: {
                orderByChild: 'quality',
                endAt: 5
            }
        });
    }
}

模板：

<div *ngFor="let thread of threads | async">
    {{thread.title}}
</div>

但是如果我想使用ngFor嵌套在模板中的另一个指令来列出子对象的键......

<div *ngFor="let thread of threads | async">
    {{thread.title}}
    <div *ngFor="let participant of thread.participants">
        {{participant.$key}}}
    </div>
</div>

我收到控制台错误， Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports …