undefined - JavaScript | MDN
The undefined global property represents the primitive value undefined. It is one of JavaScript's primitive types.| MDN Web Docs
JavaScript's strict mode is a way to opt in to a restricted variant of JavaScript, thereby implicitly opting-out of "sloppy mode". Strict mode isn't just a subset: it intentionally has different semantics from normal code. Strict mode code and non-strict mode code can coexist, so scripts can opt into strict mode incrementally.| developer.mozilla.org
The undefined global property represents the primitive value undefined. It is one of JavaScript's primitive types.| MDN Web Docs
Snaps extend the functionality of the MetaMask extension, which can then be used by connected DApps.| Least Authority
