TypeScript in 50 Lessons — Chapter One

Join us this week for Chapter One of TypeScript in 50 Lessons. Lessons include:

• Lesson 1: Red Squiggly Lines
• Lesson 2: Hunting Bugs
• Lesson 3: Types
• Lesson 4: Adding Types with JSDoc
• Lesson 5: Type Declaration Files
• Lesson 6: Ambiant Declaration Files
• Lesson 7: Tooling

Come with questions concerns, and curiosity!

This is a short-term community group for owners of the book TypeScript in 50 Lessons. The only requirement is that you own the book.

• Amazaon — Kindle-only (affiliate link)
• Smashing Magazine — all formats

Notes

Terms

• Property Descriptor, p27
• assignable, p27
• type inference, p30
• eponymous types, p34
• primitive type (number, boolean, string), p36
• composite type (object, array, function), p36
• weakly typed, p36
• strongly typed, p37
• shape, p38
• structural type system, p39
• custom type, p42
• type declaration file (.d.ts), p47
• ambiant type declarations, p53
• tsc, p58
• tsconfig.json, p60

High-level takeaways

• TM: You can use TypeScript w/o TypeScript 🤯
• VP: You can progressively adopt TypeScript tooling
• The power of IntelliSense

Additional takeaways

• MC: Love framing of “type-checking is spell-checking for code.” It minimizes the intimidation of a new language while retaining the effectiveness
• TWM: Looking at the first example, I was thinking about all the bugs we humans miss in code review
• MC: TS is like a programming pair with perfect knowledge of JavaScript
• VP: TS is excellent at helping with tricky to spot typographical errors like pluralization. e.g., CombidedDecision, combineDecisions
• TWM/BM: We can use //@ts-check privately. We don’t even have to check it into version control. Enable at and disable it locally as needed
• TWM: JS has types! It just doesn’t care about them. You have to. “Weakly typed”
• Just JavaScript shout out
• WAT, a lightning talk by Gary Bernhardt from CodeMash 2012
• MC: Do we have hope that we can sweep away the outdated practices with new ones? (the w3schools issue). New practices become legacy practices.
• BM: No. No hope 😄. Because “we don’t break the web”. Compilers are a fixed point where we can say (use this compiler version). Closest thing in JS might be Node.js version
• BM: “Don’t burninate Flash” <- If Ben was in charge of Flash marketing, we’d still have Flash
• TWM: jQuery support might be why Typescript won

Speaker

• Michael Chan

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