What the Functional? What, How and Why
summary
Argues that the core of functional programming is referential transparency and purity, then shows concrete JavaScript and Ruby examples: a pure double versus one with console.log side effects, a mutated list that breaks referential transparency, and an inefficient pipeline that iterates an array three times. Demonstrates representing IO as values and using Futures/data.task to build a parallel web‑scrape pipeline that can be forked, compares libraries (ramda, sanctuary, folktale, seamless‑immutable, immutable‑js) and type tools (Flow/TypeScript), and explains how lazy/transducer fusion avoids the multiple traversals.
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chapters (13)
- 0:00Start
- 2:15Functional Programming Pyramid
- 4:44What Is Functional Programming
- 5:04Referential Transparency
- 12:51What Does Purity Get Us
- 14:45Modularity of Evaluation
- 15:18Composition
- 16:55Expressions
- 22:25Ruby
- 27:19Immutability
- 40:08Redox Reducer
- 45:37The Competent Programmer
- 47:25Continuations
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