using Object prototype in Angular expression

Question

How can I use Object.keys(obj).length in an angular Expression?

For example, this does not work:

{{Object.keys(obj).length}}

even though

{{obj}} prints out a JSON object.

Pretty sure you got to use use a function - pass your obj to it — tymeJV
– tymeJV, Commented Mar 10, 2015 at 15:59
Yea, i figured i'd pass it into the ng-init and use it from there. just curious why Object is out of scope or something.. — d-_-b
– d-_-b, Commented Mar 10, 2015 at 16:02

Michel · Accepted Answer · 2015-03-10 16:05:54Z

3

One solution is to add Object.keys function to the scope :

$scope.getKeys = Object.keys;

And then in the template :

{{getKeys(obj).length}}

answered Mar 10, 2015 at 16:05

Michel

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1 Comment

aross Over a year ago

Good workaround. Out of my way, Angular.

dfsq · Accepted Answer · 2015-03-10 16:13:47Z

3

just curious why Object is out of scope or something

Because Object methods are not allowed in Angular expressions. Check source code for parser if you want to see what else is disallowed.

// ...
} else if (// block Object so that we can't get hold of dangerous Object.* methods
    obj === Object) {
  throw $parseMinErr('isecobj',
      'Referencing Object in Angular expressions is disallowed! Expression: {0}',
      fullExpression);
}

What you can do instead is to expose necessary method or object to the scope explicitly using $scope object.

answered Mar 10, 2015 at 16:13

dfsq

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