Language hub
JavaScript coding practice
6 focused JavaScript resources, one for each skill the diagnostic measures.
Explore JavaScriptLanguages
Unassisted coding practice by language
Pick the language you work in. Each hub collects the same six reasoning skills — code recall, tracing, debugging, finding flaws, idiomatic style, and reviewing AI-generated code — with the details that actually differ between JavaScript, TypeScript, and Python. Every resource gives a direct answer, an original example, and a small practice loop.
Language hub
TypeScript coding practice
6 focused TypeScript resources, one for each skill the diagnostic measures.
Explore TypeScriptLanguage hub
Python coding practice
6 focused Python resources, one for each skill the diagnostic measures.
Explore PythonCheck a focused starting point
One diagnostic session is a snapshot, not causal proof of why a result occurred. It can help you choose a focused next practice step without making a broader claim about your ability.
Take the free diagnosticTake the read in Python →Same six skills, side by side on your dashboard.