Why does JavaScript hoist variables and functions?
Because the engine allocates memory for all declarations during the memory allocation phase of execution context creation, before any code runs. This is a side effect, not a feature. It allows forward references and faster execution.
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More FAQs in Why JavaScript Hoists Variables and Functions
No. Hoisting is a mental model. The engine does not rearrange source code. It scans once for declarations, reserves memory, and then runs the code line-by-line.
So that functions can be called from anywhere in the scope, regardless of order. If the engine waited to store a function until its declaration line, calls earlier in the file would fail.
var was designed for loose, forgiving code (pre-ES6). let and const were introduced in ES6 to catch bugs early. The TDZ makes accessing a variable before declaration an error instead of silently returning undefined.
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