JavaScript code operates within specific environments like browsers and Node.js, each equipped with an engine that converts human-readable code into machine code. The conversion process begins with a parser checking the code's syntax and, if valid, generating an Abstract Syntax Tree (AST), which provides a structured representation of the code. The AST is then transformed into an Intermediate Representation (IR) by an interpreter, serving as a bridge between JavaScript and machine code while enabling optimizations and platform mobility. The Just-In-Time (JIT) compiler subsequently compiles the IR into optimized machine code, using real-time feedback to enhance the efficiency of repeated code segments. Although performance can be marginally improved by using objects with consistent property types and orders, the article suggests that other performance considerations are typically more impactful.