Recursive component loading with recursive array

问题:

I'm trying to load an Angular 2 component recursively with a recursive array (plunk: http://plnkr.co/edit/3npsad?p=preview).

Given this recursive array:

[
  {
    "id": 1,
    "text": "abc"
  },
  {
    "id": 2,
    "text": "def",
    items: [
      {
        "id": 21,
        "text": "def-1",
        items: [
          {
            "id": 211,
            "text": "def-1-1"
          },
          {
            "id": 212,
            "text": "def-1-2"
          }
        ]
      },
      {
        "id": 22,
        "text": "def-2"
      }
    ]
  }
]

I need the following output:

<my-item>
    <div id="1" text="abc"></div>
</my-item>
<my-item>
    <div id="2" text="def"></div>
    <my-item>
        <div id="21" text="def-1"></div>
        <my-item>
            <div id="211" text="def-1-1"></div>
        </my-item>
        <my-item>
            <div id="212" text="def-1-2"></div>
        </my-item>
    </my-item>
    <my-item>
        <div id="22" text="def-2"></div>
    </my-item>
</my-item>

I could only render the first level of input as show in my plunk. How can I make my component iterate recursively to render the desired output? The input array can contain any number of elements and nesting.

Thanks!

回答1:

update

With the introduction of @NgModule and the migration of directives to @NgModule forwardRef shouldn't be necessary anymore.

original

<my-item *ngFor="let itm of items" [id]="itm.id" [text]="itm.text" [items]="itm.items" >
</my-item>

@Component({
  selector: 'my-item',
  styles: ['div {padding-left: 32px;}']
  providers: [],
  template: `<div>{{id}} - {{text}}
    <my-item *ngFor="let itm of items" [id]="itm.id" [text]="itm.text" [items]="itm.items" >
    </my-item>
    </div>

  `,
  directives: [forwardRef(()=> ItemComponent)]
})
export class ItemComponent {
  @Input() id: string;
  @Input() text: string;
  @Input() items: any[];
  constructor() {
  }
}

forwardRef is required because the class ItemComponent is referenced before it is declared.

Plunker example

回答2:

I would create your component this way:

@Component({
  selector: 'my-item',
  template: `
    <div id="data.id" text="data.def"></div>
    <my-item *ngFor="let item of items" [data]="item"></my-item>
  `
})
export class MyItemComponent {
  @Input() data: any;
}

and call it the component from another component and provide the whole component data:

@Component({
  selector: 'other-comp',
  template: `
    <my-item [data]="data" *ngFor="let data of wholeData"></my-item>
  `
})
export class OtherComponent {
  wholeData = [
    {
      "id": 1,
      "text": "abc"
    },
    (...)
  ];
}

回答3:

Heres something to get your started. You need to implement the HTML returning function yourself:

  var a = [
  {
    "id": 1,
    "text": "abc"
  },
  {
    "id": 2,
    "text": "def",
    items: [
      {
        "id": 21,
        "text": "def-1",
        items: [
          {
            "id": 211,
            "text": "def-1-1"
          },
          {
            "id": 212,
            "text": "def-1-2"
          }
        ]
      },
      {
        "id": 22,
        "text": "def-2"
      }
    ]
  }
];

function iterateRecursive(array) {
    for(var i = 0; i < array.length; i++) {
    if(array[i].items) {
        console.log(array[i].text);
      //uncomment: printHtml(array[i].id, array[i].text);
        iterateRecursive(array[i].items)
    } else {    
        console.log(array[i].text);         
    }

  }
}


iterateRecursive(a);

//implement this function that takes an id and text and returns html
//call it in place of console log
function printHtml(id, text) {

}