SPAs are often discussed in conjunction with popular frameworks and libraries, such as AngularJS/Angular, React, Vue.js, Ember, and Meteor; but we should remember that SPAs can be written with vanilla HTML, CSS, and JavaScript alone. We may also choose to employ utility libraries, such as jQuery, to abstract away prickly web APIs, such as XMLHttpRequest, and to keep our code more readable.

However, without using a framework or library, we'd have to handle all the logic of:

• Routing: Navigating from one page to the next
• DOM manipulation: Adding/removing components to/from the page
• Data binding: Keeping the template updated with the data

This may be manageable for simply fetch-and-display applications, such as a user directory, whose main logic is to fetch data from an API, substitute it into a template, and render it. For more complicated applications, we might find ourselves re-implementing much of the features provided by a framework/library anyways. Similar to how Express abstracts low-level details to make dealing with HTTP requests and routing easier, these frameworks/libraries can abstract away a lot of logic for us.