奇怪的JavaScript变量转储

Question

When calling console.dir(myVariable) , I got this strange result:

JS: === dump(): dumping function and properties names  ===                                                                          
JS: 0:  [                                                                                                                           
JS: 1: o                                                                                                                           
JS: 2: b                                                                                                                           
JS: 3: j                                                                                                                           
JS: 4: e                                                                                                                           
JS: 5: c                                                                                                                           
JS: 6: t                                                                                                                           
JS: 7:                                                                                                                             
JS: 8: O                                                                                                                           
JS: 9: b                                                                                                                           
JS: 10: j                                                                                                                          
JS: 11: e                                                                                                                          
JS: 12: c                                                                                                                          
JS: 13: t 
JS: 14: ]
JS: === dump(): finished ===          

What does it means ? Why did I not get a standard object or array output ?

Please notice that I could not use chrome/firefox developper tool, as I am coding from Telerik NativeScript framework.

Also I am calling this code from a 'Code-Behind' for a component built in Angular 2.

This is the html for the explorer component, explorer.html :

<ActionBar title="{{ 'activity_explorer' | L }}" android.icon="res://icon"
    android.iconVisibilty="always">
    <ActionItem icon="res://icon_plus" text="{{'menuitem_new' | L}}" (tap)="showMenuItemNew()"></ActionItem>
    <ActionItem [icon]="selectionModeIcon()" text="selectionModeItemText()" (tap)="toggleSelectionMode()"></ActionItem>
</ActionBar>

<GridLayout rows="1*, 12*" modal-dialog-host>

    <Label class="path_component" row="0" [text]="_path" textWrap="true"> </Label>

    <ListView row="1" [items]="_files">
        <template let-item="item">
            <loloof64-explorer-item-line [checkboxVisible]="_selectionMode" item="{{item}}"></loloof64-explorer-item-line>
        </template>
    </ListView>

 </GridLayout>

This is the html for explorer_item_line component : explorer_item_line.html

<GridLayout columns="1*, 1*, 7*">
    <loloof64-checkbox #check_comp col="0" [visible]="checkboxVisible"> </loloof64-checkbox>
    <Image col="1"  (tap)="handleTap()" src="res://folder"></Image>
    <Label col="2"  (tap)="handleTap()" text="Text" textWrap="true">   </Label>
</GridLayout>

This is the ExploreItem class :

export class ExplorerItem {

    private _name: string;
    private _isDirectory: boolean;

    constructor(name: string, isDirectory: boolean){
        this._name = name;
        this._isDirectory = isDirectory;
    }

    name(){
        return this._name;
    }

    isDirectory(){
        return this._isDirectory;
    }

    public isParent() : boolean {
        return this._name === ".." && this._isDirectory;
    }

    public static sort(left: ExplorerItem, right: ExplorerItem): number {
        if (left.isDirectory() === right.isDirectory()) { 
            return left.name().toLowerCase().localeCompare(right.name().toLowerCase());
        }
        else {
            return left.isDirectory() ? -1 : 1;
        }
    }
}

This is the explorer_item_line.ts :

import {Component, Input, ViewChild} from '@angular/core';
import {Checkbox} from "../checkbox/checkbox";
import {ExplorerItem} from "./explorer_item";

import * as _ from 'lodash';

@Component({
    moduleId: module.id,
    selector: 'loloof64-explorer-item-line',
    templateUrl: 'explorer_item_line.html',
    styleUrls: ['explorer_item_line.css'],
    directives: [Checkbox]
})
export class ExplorerItemLine {
    @Input() checkboxVisible: boolean = false;
    @Input() item: any;
    @ViewChild('check_comp') checkboxComp: Checkbox;

    handleTap(){
        if (this.checkboxVisible){
            this.checkboxComp.checked = ! this.checkboxComp.checked;
        }

        console.log(JSON.stringify(this.item))
    }
}

I think it is a binding problem between the explorer and explorer_item_line components, but I can't figure why and how to solve it.

And finally, I land on Nativescript debugging page : so I should be able to inspect it in Chrome's developper tool.

Answer 1

item="{{item}}是NativeScript核心绑定的语法..其中NativeScript + Angular-2您应该使用ng-style，这意味着[item]="item"在ng-app中使用核心语法会导致该值返回的类型为[object Object]而不是您期望的值。