Type-Level-Programming on Dev & Platform Engineering Hub

TS Ep 3: Advanced TypeScript — Conditional Types, Infer Keyword, and Template Literal Metaprogramming

Sun, 09 Aug 2026 13:30:00 +0000

An advanced masterclass in TypeScript type-level metaprogramming. Master conditional types (T extends U ? X : Y), distributive behavior, infer keyword pattern matching for unwrapping types, template literal types (${T}_${U}), and deep recursive object transformations.

TS Ep 52: Variance (Covariance vs Contravariance)

Sun, 09 Aug 2026 13:30:00 +0000

Why is it safe to return a subclass instead of a superclass, but dangerous to accept a superclass parameter instead of a subclass? Welcome to Variance: the computer science underpinning of TypeScript’s assignability engine.

TS Ep 51: Type-Level State Machines

Sun, 09 Aug 2026 13:25:00 +0000

Use mapped types and generics to enforce finite state transitions in the compiler. A type-level state machine makes impossible states impossible to represent, eliminating entire classes of runtime bugs.

TS Ep 49: Recursive Types

Sun, 09 Aug 2026 13:15:00 +0000

How do you type a JSON object? A JSON object can contain arrays of objects, which can contain arrays of objects, infinitely down. You cannot hardcode this depth. You need a Recursive Type.

TS Ep 47: Template Literal Types

Sun, 09 Aug 2026 13:05:00 +0000

Template literal types allow you to use JavaScript-style template strings (${...}) inside Type Space. Learn how to generate combinations of string literals automatically via Union Permutation, and parse delimited strings (like emails or URLs) using the infer keyword.

TS Ep 46: Inferring Tuples and Arrays

Sun, 09 Aug 2026 13:00:00 +0000

Pattern matching with infer isn’t just for Promises and Objects. You can deconstruct Tuples and Arrays element by element in Type Space, mirroring the exact syntax of JavaScript’s array destructuring and spread operators.

TS Ep 44: The `infer` Keyword (Pattern Matching)

Sun, 09 Aug 2026 12:50:00 +0000

If conditional types are the if-else statements of Type Space, the infer keyword is the variable declaration (let x = ...). Learn how to extract types dynamically via pattern matching, rebuild ReturnType, and parse Template Literal Strings at compile time.

TS Ep 43: Preventing Distribution (Tuples)

Sun, 09 Aug 2026 12:45:00 +0000

Sometimes, you want a conditional type to evaluate an entire Union as a single monolithic entity, rather than mapping over its individual members. Learn how wrapping generic parameters in brackets [T] prevents distribution, and how to use this mechanic to build complex IsUnion checks.

TS Ep 42: Distributive Conditional Types

Sun, 09 Aug 2026 12:40:00 +0000

When you pass a Union type into a conditional type, TypeScript doesn’t evaluate the union as a whole. It evaluates every single member of the union separately, and combines the results. Learn how this powerful (and sometimes confusing) mechanism powers TypeScript’s standard library.

TS Ep 41: Conditional Types (The Basics)

Sun, 09 Aug 2026 12:35:00 +0000

Conditional types are the if-else statements of Type Space. Learn how to use the ’extends ? :’ syntax to compute dynamic types based on assignability logic, replace complex function overloads, and construct nested else-if type chains.

TS Ep 40: Key Remapping with `as`

Sun, 09 Aug 2026 12:30:00 +0000

Take your Mapped Types to the absolute limit. Learn how to compute entirely new string names for keys on the fly using Template Literal Types, and discover how to completely filter out properties by returning never during key mapping.

TS Ep 38: Mapped Types (Basics)

Sun, 09 Aug 2026 12:20:00 +0000

An in-depth guide to Mapped Types in TypeScript. Learn how to use the [K in Union] syntax to iterate over literal unions, transform existing object properties using keyof and Indexed Access, and build strict state validation maps that perfectly mirror domain models.

Mastering TypeScript: From Fundamentals to Type-Level Programming & Functional Effect-TS

Sun, 09 Aug 2026 12:00:00 +0000

The ultimate TypeScript masterclass roadmap. Master primitive types, type narrowing, generics, mapped types, conditional types, infer keyword, template literal types, type-level state machines, and functional Effect-TS architecture.

TS Ep 27: The `keyof` Type Operator

Sun, 09 Aug 2026 11:25:00 +0000

An exhaustive guide to the keyof operator in TypeScript. Learn how keyof extracts property key unions from object interfaces, array/tuple types, index signatures, and how to combine keyof with Generics to build type-safe property accessors.