Engineering notes

How the tools are built.

Parsers, encoders and algorithms written from scratch in TypeScript — what we learned building each devprix tool.

Latest posts

4 deep-dives so far.

March 28, 202612 min read

Building a SQL Tokenizer and Formatter From Scratch — Supporting 6 Dialects

A deep dive into building a SQL tokenizer and formatter that handles PostgreSQL, MySQL, SQL Server, Oracle, SQLite, and BigQuery — using a two-stage pipeline with no AST required.

SQLTypeScriptParsingCompilersRead the post

type TokenType =
  | "keyword" | "identifier" | "string" | "number"
  | "operator" | "punctuation" | "comma"
  | "open_paren" | "close_paren"
  | "comment_single" | "comment_multi"
  | "whitespace" | "dot" | "semicolon"
  | "wildcard" | "unknown";

interface Token {
  type: TokenType;
  value: string;
}

March 24, 202611 min read

Implementing the Myers Diff Algorithm in TypeScript — Character-Level Precision

How I implemented the Myers diff algorithm with character-level highlighting — the same algorithm behind git diff, built from scratch in TypeScript.

TypeScriptAlgorithmsDiffGitRead the post March 21, 202614 min read

I Built a QR Code Encoder From Scratch in TypeScript — Here's How It Works

A deep dive into implementing the entire QR encoding pipeline from scratch — Reed-Solomon error correction, Galois Field arithmetic, mask pattern optimization, and all.

TypeScriptQR CodeAlgorithmsReed-SolomonRead the post March 18, 20268 min read

I Built 56 Developer Tools With Zero Dependencies — Here's What I Learned

How I built devprix.io — 56 free, privacy-focused developer tools that all run client-side with zero npm dependencies for tool logic.

JavaScriptWeb DevProductivityOpen SourceRead the post

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