Edit in JSFiddle

<div ng-app=""> 
    <p ng-class="{strike: deleted, bold: important, red: error}">Map Syntax Example</p>
    <label>
       <input type="checkbox" ng-model="deleted">
       deleted (apply "strike" class)
    </label><br>
    <label>
       <input type="checkbox" ng-model="important">
       important (apply "bold" class)
    </label><br>
    <label>
       <input type="checkbox" ng-model="error">
       error (apply "red" class)
    </label>
</div>    

.strike {
    text-decoration: line-through;
}
.bold {
    font-weight: bold;
}
.red {
    color: red;
}
.orange {
    color: blue;
}