FrontendHaltJavaScript·Intermediate·Conceptual·1 min read
What is default this in strict mode?
Short interview answer
A plain call to an ordinary strict-mode function receives undefined. In sloppy mode it may substitute the global object and box primitives. ES modules and class bodies use strict semantics, so relying on sloppy default binding is fragile.
Key takeaway
Explain the underlying mental model clearly, then support it with a concrete example and its trade-offs.