Losing scope when using ng-include

Instead of using this as the accepted answer suggests, use $parent instead. So in your partial1.htmlyou'll have:

<form ng-submit="$parent.addLine()">
    <input type="text" ng-model="$parent.lineText" size="30" placeholder="Type your message here">
</form>

If you want to learn more about the scope in ng-include or other directives, check this out: https://github.com/angular/angular.js/wiki/Understanding-Scopes#ng-include

This is because of ng-include which creates a new child scope, so $scope.lineText isn’t changed. I think that this refers to the current scope, so this.lineText should be set.

As @Renan mentioned, ng-include creates a new child scope. This scope prototypically inherits (see dashed lines below) from the HomeCtrl scope. ng-model="lineText" actually creates a primitive scope property on the child scope, not HomeCtrl's scope. This child scope is not accessible to the parent/HomeCtrl scope:

To store what the user typed into HomeCtrl's $scope.lines array, I suggest you pass the value to the addLine function:

 <form ng-submit="addLine(lineText)">

In addition, since lineText is owned by the ngInclude scope/partial, I feel it should be responsible for clearing it:

 <form ng-submit="addLine(lineText); lineText=''">

Function addLine() would thus become:

$scope.addLine = function(lineText) {
    $scope.chat.addLine(lineText);
    $scope.lines.push({
        text: lineText
    });
};

Fiddle.

Alternatives:

• define an object property on HomeCtrl's $scope, and use that in the partial: ng-model="someObj.lineText; fiddle
• not recommended, this is more of a hack: use $parent in the partial to create/access a lineText property on the HomeCtrl $scope:  ng-model="$parent.lineText"; fiddle

It is a bit involved to explain why the above two alternatives work, but it is fully explained here: What are the nuances of scope prototypal / prototypical inheritance in AngularJS?

I don't recommend using this in the addLine() function. It becomes much less clear which scope is being accessed/manipulated.