A Tale of Types, Classes, and Maps
summary
Maps out how JavaScript engines turn object shapes into concrete runtime structures and what actually moves performance: hidden classes (maps) that record property order, inline caches that specialize lookups, and the shift to dictionary mode when shapes become polymorphic. Builds small microbenchmarks and inspects engine traces and memory layouts to show which code patterns force deoptimizations, measures lookup and allocation cost changes, and implements simple rewrites that produce consistent, verifiable speedups.
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chapters (7)
- 0:00Introduction
- 5:46Type systems in programming
- 12:11Class-based abstractions
- 20:40Map data structures
- 28:12Performance implications
- 35:49Use cases and examples
- 39:49Q&A
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