Angular JS: Detect if ng-bind-html finished loading then highlight code syntax

问题

I am using ng-bind-html for binding data that I get from database.

<p ng-bind-html="myHTML"></p>   


app.controller('customersCtrl', function($scope, $http, $stateParams) {
    console.log($stateParams.id);
    $http.get("api link"+$stateParams.id)
    .then(function(response) {
      $scope.myHTML = response.data.content;

        // this will highlight the code syntax
        $('pre code').each(function(i, block) {
            hljs.highlightBlock(block);
        });
    });
});

When the data displayed on the screen, I want to run

$('pre code').each(function(i, block) {
      hljs.highlightBlock(block);
});

for highlight the code syntax in the data but it is not highlight. (I use highlight library in CKEditor for highlight the code syntax)

And if I delay load the highlight code after 1s, it will work but I think it is not a good solution

setTimeout(function () {
    $('pre code').each(function(i, block) {
        hljs.highlightBlock(block);
    });
  }, 1000);

I think maybe the highlight code run before ng-bind-html finished.

=== UPDATE
I am using $timeout with delay time 0 as some person recommend. However, sometime when the network is slow and the page load slow, the code will not highlighted .

$scope.myHTML = response.data.content;
$timeout(function() {
  $('pre code').each(function(i, block) {
      hljs.highlightBlock(block);
  });
}, 0);

回答1:

This is where directives come in very handy. Why not append the HTML yourself and then run the highlighter?

Template:

<div ng-model="myHTML" highlight></div>

Directive:

.directive('highlight', [
    function () {
        return {
            replace: false,
            scope: {
                'ngModel': '='
            },
            link: function (scope, element) {
                element.html(scope.ngModel);
                var items = element[0].querySelectorAll('code,pre');
                angular.forEach(items, function (item) {
                    hljs.highlightBlock(item);
                });

            }
        };
    }
]);

Example: http://plnkr.co/edit/ZbcNgfl6xL2QDDqL9cKc?p=preview

回答2:

So here's what is happening:

You update the $scope.myHTML value
You run your jQuery each() loop
The digest cycle runs and your template is updated

Notice that the digest cycle runs after your jQuery each() loop -- or, more specifically, after your $http callback function is finished running.

That means the value of $scope.myHTML in your controller is not applied to the ng-bind-html directive until after your loop has already finished.

To overcome this, you could use Angular's $timeout service instead of the native browser setTimeout() method. By default, $timeout will invoke the callback function during the next digest cycle, which means it will run after the changes to $scope.myHTML are applied to the ng-bind-html directive (as long as you update $scope.myHTML before calling $timeout()).

Working example: JSFiddle

回答3:

as you know the statements execute asynchronously, if there is no timeout $('pre code') will be empty as the DOM is still not rendered. use $timeout instead of setTimeout for the same.

来源：https://stackoverflow.com/questions/34215052/angular-js-detect-if-ng-bind-html-finished-loading-then-highlight-code-syntax

标签

angularjs

syntax-highlighting

ng-bind-html