# JavaScript Hoisting — What Actually Happens Behind the Scenes ?

Short summary

This article explains JavaScript hoisting as a memory allocation process during the engine's creation phase, not physical code movement. It covers how var, let, const, and function declarations are handled differently during this phase, including the Temporal Dead Zone for let/const. The piece also introduces execution contexts and the call stack to show how the engine manages code execution.

• •Hoisting is memory allocation during the creation phase, not code movement
• •var initializes to undefined; let/const sit uninitialized in the Temporal Dead Zone
• •Function declarations are fully stored in memory; function expressions assigned to var are not

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