Is there any way to make an expression for something like ng-class to be a conditional?
For example, I have tried the following:
<span ng-class="{test: 'obj.value1 == \'someothervalue\''}">test</span>
The issue with this code is that no matter what obj.value1 is, the class test is always applied to the element. Doing this:
<span ng-class="{test: obj.value2}">test</span>
As long as obj.value2 does not equal a truthy value, the class in not applied. Now I can work around the issue in the first example by doing this:
<span ng-class="{test: checkValue1()}">test</span>
Where the checkValue1 function looks like this:
$scope.checkValue1 = function() {
return $scope.obj.value === 'somevalue';
}
I am just wondering if this is how ng-class is supposed to work. I am also building a custom directive where I would like to do something similar to this. However, I can't find a way to watch an expression (and maybe that is impossible and the reason why it works like this).
Here is a plnkr to show what I mean.
Your first attempt was almost right, It should work without the quotes.
{test: obj.value1 == 'someothervalue'}
Here is a plnkr.
The ngClass directive will work with any expression that evaluates truthy or falsey, a bit similar to Javascript expressions but with some differences, you can read about here.
If your conditional is too complex, then you can use a function that returns truthy or falsey, as you did in your third attempt.
Just to complement: You can also use logical operators to form logical expressions like
ng-class="{'test': obj.value1 == 'someothervalue' || obj.value2 == 'somethingelse'}"
Using ng-class inside ng-repeat
<table>
<tbody>
<tr ng-repeat="task in todos"
ng-class="{'warning': task.status == 'Hold' , 'success': task.status == 'Completed',
'active': task.status == 'Started', 'danger': task.status == 'Pending' } ">
<td>{{$index + 1}}</td>
<td>{{task.name}}</td>
<td>{{task.date|date:'yyyy-MM-dd'}}</td>
<td>{{task.status}}</td>
</tr>
</tbody>
</table>
For each status in task.status a different class is used for the row.
Angular JS provide this functionality in ng-class Directive. In which you can put condition and also assign conditional class. You can achieve this in two different ways.
Type 1
<div ng-class="{0:'one', 1:'two',2:'three'}[status]"></div>
In this code class will be apply according to value of status value
if status value is 0 then apply class one
if status value is 1 then apply class two
if status value is 2 then apply class three
Type 2
<div ng-class="{1:'test_yes', 0:'test_no'}[status]"></div>
In which class will be apply by value of status
if status value is 1 or true then it will add class test_yes
if status value is 0 or false then it will add class test_no
I see great examples above but they all start with curly brackets (json map). Another option is to return a result based on computation. The result can also be a list of css class names (not just map). Example:
ng-class="(status=='active') ? 'enabled' : 'disabled'"
or
ng-class="(status=='active') ? ['enabled'] : ['disabled', 'alik']"
Explanation: If the status is active, the class enabled will be used. Otherwise, the class disabled will be used.
The list [] is used for using multiple classes (not just one).
There is a simple method which you could use with html class attribute and shorthand if/else. No need to make it so complex. Just use following method.
<div class="{{expression == true ? 'class_if_expression_true' : 'class_if_expression_false' }}">Your Content</div>
I am going to show you two methods by which you can dynamically apply ng-class
Step-1
By using ternary operator
<div ng-class="condition?'class1':'class2'"></div>
Output
If your condition is true then class1 will be applied to your element else class2 will be applied.
Disadvantage
When you will try to change the conditional value at run time the class somehow will not changed. So I will suggest you to go for step2 if you have requirement like dynamic class change.
Step-2
<div ng-class="{value1:'class1', value2:'class2'}[condition]"></div>
Output
if your condition matches with value1 then class1 will be applied to your element, if matches with value2 then class2 will be applied and so on. And dynamic class change will work fine with it.
Hope this will help you.
Angular syntax is to use the : operator to perform the equivalent of an if modifier
<div ng-class="{ 'clearfix' : (row % 2) == 0 }">
Add clearfix class to even rows. Nonetheless, expression could be anything we can have in normal if condition and it should evaluate to either true or false.
Using function with ng-class is a good option when someone has to run complex logic to decide the appropriate CSS class.
http://jsfiddle.net/ms403Ly8/2/
HTML:
<div ng-app>
<div ng-controller="testCtrl">
<div ng-class="getCSSClass()">Testing ng-class using function</div>
</div>
</div>
CSS:
.testclass { Background: lightBlue}
JavaScript:
function testCtrl($scope) {
$scope.getCSSClass = function() {
return "testclass ";
}
}
For Angular 2, use this
<div [ngClass]="{'active': dashboardComponent.selected_menu == 'mapview'}">Content</div>
use this
<div ng-class="{states}[condition]"></div>
for example if the condition is [2 == 2], states are {true: '...', false: '...'}
<div ng-class="{true: 'ClassA', false: 'ClassB'}[condition]"></div>
ng-class is a Directive of core AngularJs. In which you can use "String Syntax", "Array Syntax", "Evaluated Expression", " Ternary Operator" and many more options described below:
ngClass Using String Syntax
This is the simplest way to use ngClass. You can just add an Angular variable to
ng-class and that is the class that will be used for that element.
<!-- whatever is typed into this input will be used as the class for the div below -->
<input type="text" ng-model="textType">
<!-- the class will be whatever is typed into the input box above -->
<div ng-class="textType">Look! I'm Words!
Demo Example of ngClass Using String Syntax
ngClass Using Array Syntax
This is similar to the string syntax method except you are able to apply multiple classes.
<!-- both input boxes below will be classes for the div -->
<input type="text" ng-model="styleOne">
<input type="text" ng-model="styleTwo">
<!-- this div will take on both classes from above -->
<div ng-class="[styleOne, styleTwo]">Look! I'm Words!
ngClass Using Evaluated Expression
A more advanced method of using ngClass (and one that you will probably use the most) is to evaluate an expression. The way this works is that if a variable or expression evaluates to true, you can apply a certain class. If not, then the class won't be applied.
<!-- input box to toggle a variable to true or false -->
<input type="checkbox" ng-model="awesome"> Are You Awesome?
<input type="checkbox" ng-model="giant"> Are You a Giant?
<!-- add the class 'text-success' if the variable 'awesome' is true -->
<div ng-class="{ 'text-success': awesome, 'text-large': giant }">
Example of ngClass Using Evaluated Expression
ngClass Using Value
This is similar to the evaluated expression method except you just able to compares multiple values with the only variable.
<div ng-class="{value1:'class1', value2:'class2'}[condition]"></div>
ngClass Using the Ternary Operator
The ternary operator allows us to use shorthand to specify two different classes, one if an expression is true and one for false. Here is the basic syntax for the ternary operator:
ng-class="$variableToEvaluate ? 'class-if-true' : 'class-if-false'">
Evaluating First, Last or Specific Number
If you are using the ngRepeat directive and you want to apply classes to the first, last, or a specific number in the list, you can use special properties of ngRepeat. These include $first, $last, $even, $odd, and a few others. Here's an example of how to use these.
<!-- add a class to the first item -->
<ul>
<li ng-class="{ 'text-success': $first }" ng-repeat="item in items">{{ item.name }}</li>
</ul>
<!-- add a class to the last item -->
<ul>
<li ng-class="{ 'text-danger': $last }" ng-repeat="item in items">{{ item.name }}</li>
</ul>
<!-- add a class to the even items and a different class to the odd items -->
<ul>
<li ng-class="{ 'text-info': $even, 'text-danger': $odd }" ng-repeat="item in items">{{ item.name }}</li>
</ul>
I have an element that is repeated.
<li ng-repeat="plan in displayedPlans"> ... </li>
I'd like to add limitTo to it to show the first two plans.
<li ng-repeat="plan in displayedPlans|limitTo:2"> ... </li>
But now I want limitTo to only apply if a boolean (called "experiment" in this example) is true. One of the ways I tried to accomplish my goal is something like this (which didn't work) -
<li ng-repeat="plan in displayedPlans, plan in displayedPlans|limitTo:2 : experiment"> ... </li>
I also tried putting the ng-repeat value in curly braces and separating the two options with || but that didn't work. I'm wondering if there is a clean solution I can use in the HTML.
Change the value of limitTo depending on experiment. It its true set it to 2, else 10000.
I have an outer div that I want to repeat for each cats in art.Categories.
While that repeat loop happens, I want to take the value from the ng-repeat and use it to create a nested ng-repeat. This nested ng-repeat will continue until it runs out of items, then return to the outside ng-repeat, which will continue the process.
My issue is I can't use {{cats.id}} as the filter for the sub-Div.
<div ng-repeat="cats in art.Categories" class="tab-pane" ng-class="{active: $index == 0}" id="{{cats.id}}">
<div ng-repeat="arts in art.Articles | filter: { ids: '{{cats.id}}' }" class="entity_container"></div>
</div>
As the commenter mentioned, a solution is to remove the curly braces. In my example, that means just writing cats.id. As an aside, I need to implement UI's native tabs directives.
Try this:
ng-show="arts.ids==cats.id"
I have an array of 3 items and want them to be "ng-repeated"
<li ng-repeat="item in obj.items id="testobj{{testobj.number}}">
</li>
When I look at the page, it appears that the id of the "li" is just "testobj" for all 3 items and not testobj1 testobj2 testobj3 like I was expecting. What is the issue?
Your ng-repeat attribute is missing a final ".
The {{ }} binding is probably coming back with no data and so being treated as if it was an empty string. I see no reference to testobj (the scope variable) anywhere outside of your binding. Is this defined, or should your id read id="testobj{{item.number}}" or something similar?
The Angular docs are really sparse on what is acceptable in an "expression" within a conditional ng-class.
For example, I'm running an ng-repeat over a list:
<ul class="clothes">
<li ng-repeat="piece in clothes | filter:query">
{{piece.name}}
</li>
</ul>
On every third <li> element I'd like to add a class of "third". Can this be done using ng-class with something like ng-class="{third : li:nth-child(3)}" or similar?
Side-note, is there a general reference somewhere that defines and gives examples of what can be used in an Angular expression? There's some really basic stuff that I can do with vanilla Javascript/css but I can't work out how to cram it into Angular!
Just create an expression that evaluates to true or false, a bit similar to Javascript expressions but with some differences, you can read about it here.
<ul>
<li ng-repeat="item in items" ng-class="{third: !(($index+1)%3) && !$first }">{{item}}</li>
</ul>
Here is a jsBin.
In my code I am telling ng-class to add the class 'third' when ($index+1)%3 is zero and it is not the $first list item ($index, $first and $last are created by ng-repeat).
if you want to use css instead of angular for the styling, you can use the css nth selector
http://www.w3schools.com/cssref/sel_nth-child.asp
li:nth-child(3n+3)
{
background:#ff0000;
}