How would you migrate a codebase from jQuery to plain JavaScript or a framework?

Summary

Incrementally: stop adding new jQuery code, replace jQuery utilities with native equivalents module by module (selectors, classList, fetch, events), and move complex interactive widgets to components in the target framework, mounting them inside the existing pages. Keep both running during the transition and remove jQuery when nothing depends on it.

Longer Answer

Practical steps: measure where jQuery is used (lint rules such as eslint-plugin-no-jquery can flag usage and block new code), write tests around critical behaviour first, start with leaf features, and watch out for plugins (date pickers, sliders) that have no drop-in replacement. A framework and jQuery should not manipulate the same DOM nodes, or the framework will overwrite jQuery's changes (and vice versa).

For server-rendered apps, lightweight tools such as Alpine.js or htmx can replace much jQuery code with less JavaScript.

Key Points

• Stop new jQuery; migrate incrementally.
• Native APIs for utilities.
• Framework components for complex widgets.
• Never share DOM nodes between jQuery and a framework.

What interviewers look for

A phased, test-protected plan instead of a big-bang rewrite.