在日历的对象数组上使用ngFor

Question

How would I use ngFor to loop through the following object array and get only the names of the months?

{
  "Jan": {
    "name": "January",
    "short": "Jan",
    "number": 1,
    "days": 31
  },
  "Feb": {
    "name": "February",
    "short": "Feb",
    "number": 2,
    "days": 28
  },
  "Mar": {
    "name": "March",
    "short": "Mar",
    "number": 3,
    "days": 31
  },
  "Apr": {
    "name": "April",
    "short": "Apr",
    "number": 4,
    "days": 30
  },
  "May": {
    "name": "May",
    "short": "May",
    "number": 5,
    "days": 31
  },
  "Jun": {
    "name": "June",
    "short": "Jun",
    "number": 6,
    "days": 30
  },
  "Jul": {
    "name": "July",
    "short": "Jul",
    "number": 7,
    "days": 31
  },
  "Aug": {
    "name": "August",
    "short": "Aug",
    "number": 8,
    "days": 31
  },
  "Sep": {
    "name": "September",
    "short": "Sep",
    "number": 9,
    "days": 30
  },
  "Oct": {
    "name": "October",
    "short": "Oct",
    "number": 10,
    "days": 31
  },
  "Nov": {
    "name": "November",
    "short": "Nov",
    "number": 11,
    "days": 30
  },
  "Dec": {
    "name": "December",
    "short": "Dec",
    "number": 12,
    "days": 31
  }
}

This is what I have done so far:

<option *ngFor="let date of dates" 
 [ngValue]="date.name" [(ngModel)]="dobMonth">{{ date.name }}</option>

Result:

Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays.

Answer 1

Use | keyvalue | keyvalue pipe!

angular 6.0.0 onwards | keyvalue | keyvalue pipe added to render object in *ngFor .

<option *ngFor="let date of dates | keyvalue" 
 [ngValue]="date.name" [(ngModel)]="dobMonth">{{ date.name }}</option>

Answer 2

*ngFor cannot be used to loop over object properties. You'll need to convert the object to an iterable data type first.

let dateArray = Object.values(dates) // --> [{"name": "January", "short": "Jan", ...} ...]

in the markup:

<option *ngFor="let date of dateArray" 
  [ngValue]="date.name" [(ngModel)]="dobMonth">{{ date.name }}</option>

or if you're using version 6+, just use the keyvalue pipe:

<option *ngFor="let date of dates | keyvalue" 
 [ngValue]="date.name" [(ngModel)]="dobMonth">{{ date.name }}</option>