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TypeScript Academy · Lesson

Designing a Fluent Query DSL

Build a chainable, self-validating query API.

Designing a Fluent Query DSL

We design a chainable query DSL where each step refines the allowed next steps via return types. The result reads like SQL and rejects invalid orderings at compile time.

The Target Grammar

We want: from then optional where (repeatable) then a terminal select. You cannot select before from, and you cannot from twice.

All lessons in this course

  1. What Is a Type-Level DSL
  2. Designing a Fluent Query DSL
  3. Compile-Time Input Validation
  4. Error Messages in Type-Level DSLs
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