Currently, I am utilizing MEAN (MongoDB Express Angular Node) to connect my dropdown in angular 2 with MongoDB values in the backend.
In my node JS, I have defined routes and models as shown below:
\var\www\html\Express\nodeauthapp-master\routes\categories.js
//Get all categories
router.get('/get',(req,res,next) => {
//res.send('Get categories');
Categories.getAllCategories((err,categories)=>{
if(err)
{
res.json({success: false, msg:'Failed to get categories'});
}
else
{
res.json({success: true, mainCategories:categories});
}
});
})
\var\www\html\Express\nodeauthapp-master\models\categories.js
// Categories Schema
const CategoriesSchema = mongoose.Schema({
category_name: {
type: String,
required: true
}
});
const Categories = module.exports = mongoose.model('Categories', CategoriesSchema);
//Get all categories
module.exports.getAllCategories = function(callback){
Categories.find({},callback)
}
For binding the dropdown in Angular 2, I use the following method:
blank-page.component.html
<form role="form">
<fieldset class="form-group">
<label>Select Category</label><br/><br/>
<select [(ngModel)]="selectedObject" name="selectedObject" class="form-control">
<option disabled>--Select--</option>
<option *ngFor="let category of categories" [value]="category">{{category}}</option>
</select>
</fieldset>
</form>
blank-page.component.ts
export class BlankPageComponent implements OnInit {
category:String;
public categories: Array<any> = [];
constructor(private addproductService: AddproductService,
private flashMessage: FlashMessagesService,
private router: Router) { }
ngOnInit() {
const category = {
categories: this.category
}
console.log(category);
this.addproductService.loadData(category).subscribe(data => {
if(data.success){
this.categories = data.mainCategories;
console.log('Dropdown bound successfully');
} else {
console.log('Not bound');
}
});
}
addproduct.service.ts
export class AddproductService {
category: any;
loadData(category) {
let headers = new Headers();
headers.append('Content-Type', 'application/json');
return this.http.get('http://10.*.*.*:3000/categories/get', { headers: headers })
.map(res => res.json());
}
}
The console log shows that the dropdown is successfully bound, however, in the frontend, no values are being bound.
When I access the GET API URL in Postman, I can see the list of categories.
In the browser logs, I receive: Object {categories: undefined}
My object contains: https://i.stack.imgur.com/lWhWW.jpg