What is the difference between AngularJS and Angular?
Why Interviewers Ask This
Interviewers use this question to quickly assess whether a candidate has the foundational knowledge required for Angular development. It reveals whether you understand the building blocks that more complex concepts rely on.
Answer
AngularJS (Angular 1.x) was the original framework released in 2010. Angular (2+) is a complete rewrite released in 2016. They are fundamentally different frameworks sharing only a name. Key differences: Language: AngularJS used JavaScript; Angular uses TypeScript (with JavaScript support). Architecture: AngularJS used MVC (Model-View-Controller) pattern with scopes and controllers; Angular uses component-based architecture — everything is a component. Data binding: AngularJS used two-way data binding everywhere (dirty checking with $scope — performance issues at scale); Angular uses one-way data flow by default with optional two-way binding ([(ngModel)]), and change detection is much more efficient. Dependency injection: AngularJS had a string-based DI system (fragile, especially with minification); Angular has a hierarchical DI system based on TypeScript type annotations. Performance: AngularJS used digest cycles for change detection (slow for large apps); Angular uses zones and smarter change detection (OnPush strategy available). Mobile support: AngularJS was not designed for mobile; Angular has NativeScript and Ionic support. CLI: AngularJS had no official CLI; Angular has the powerful Angular CLI. Modularity: AngularJS had limited module system; Angular has NgModules (and now standalone components). AngularJS reached end-of-life in December 2021.
Pro Tip
Before answering, structure your response: one-line definition → real-world analogy → concrete example from a project. This makes even complex Angular answers easy to follow.