Use svg with angularjs ng-repeat

Question

I am learning angularjs and I am trying use ng-repeat to create an svg graph.

I have this html:

<svg>
    <g id="g_{{$index}}" ng-repeat="i in range" ng-cloak>
        <rect x="{{i / 5}}" y="{{i / 5}}" width="{{i / 5}}" height="{{i / 5}}"></rect>
    </g>
</svg>

the 'range' is just a simple array which is defined in controller like this:

$scope.range = [100, 200, 300];

the html is working; the rects are rendered on my page.

However, Chrome keeps throwing the following error:

Error: Invalid value for <rect> attribute height="{{i / 5}}"    js/angular.js:1584
  JQLiteClone   js/angular.js:1584
  JQLite.(anonymous function)   js/angular.js:2163
  publicLinkFn  js/angular.js:3862
  ngRepeatWatch js/angular.js:13641
  Scope.$digest js/angular.js:7889
  Scope.$apply  js/angular.js:8097
    js/angular.js:961
  invoke    js/angular.js:2857
  resumeBootstrapInternal   js/angular.js:959
  bootstrap js/angular.js:973
  angularInit   js/angular.js:934
    js/angular.js:14756
  fire  js/jquery-2.0.0.js:2863
  self.fireWith js/jquery-2.0.0.js:2975
  jQuery.extend.ready   js/jquery-2.0.0.js:398
  completed js/jquery-2.0.0.js:93

It seems that it does not quite like what I am doing...

Does anyone have an idea why I'm receiving this error?

Answer 1

The problem is Chrome sees the Angular interpolation str as an invalid value for those attributes (since at least at one time the element actually exists in the DOM -- though invisibly -- with "invalid" values). I have written a solution that is in line with other Angular solutions as to browser handling of special attributes where instead of using x, y, width, and height, you specify ng-x, ng-y, ng-width, and ng-height and the real attributes are set after the values are interpolated.

Here is the solution on JSFiddle. I'm going to submit a patch to Angular to see if we can get this in the core.

HTML

<div ng-app="SampleApp" ng-controller="MainCtrl">
    <svg>
        <g id="g_{{$index}}" ng-repeat="i in range" ng-cloak>
            <rect ng-x="{{i / 5}}" ng-y="{{i / 5}}" ng-width="{{i / 5}}" ng-height="{{i / 5}}"></rect>
        </g>
    </svg>
</div>

JS

angular.module('SampleApp', [], function() {})
    .directive('ngX', function() {
        return function(scope, elem, attrs) {
            attrs.$observe('ngX', function(x) {
                elem.attr('x', x);
            });
        };
    })
    .directive('ngY', function() {
        return function(scope, elem, attrs) {
            attrs.$observe('ngY', function(y) {
                elem.attr('y', y);
            });
        };
    })
    .directive('ngWidth', function() {
        return function(scope, elem, attrs) {
            attrs.$observe('ngWidth', function(width) {
                elem.attr('width', width);
            });
        };
    })
    .directive('ngHeight', function() {
        return function(scope, elem, attrs) {
            attrs.$observe('ngHeight', function(height) {
                elem.attr('height', height);
            });
        };
    });

function MainCtrl($scope) {
    $scope.range = [100, 200, 300];
}

Answer 2

Markus' comment to use late binding is best.

Ie. prefix your attribute with either 'ng-attr-', 'ng:attr:' or 'ng_attr_', like this:

<rect ng:attr:x="{{i / 5}}" ng:attr:y="{{i / 5}}" ng:attr:width="{{i / 5}}" nng:attr:height="{{i / 5}}"></rect>