AI Summary
→ WHAT IT COVERS James Long, creator of Prettier, joins Josh Goldberg on Software Engineering Daily to discuss how the opinionated JavaScript formatter emerged from code-style debates at Mozilla, why deterministic formatting removes team friction, the technical complexity of building formatters, and the financial realities of sustaining popular open source tooling. → KEY INSIGHTS - **Opinionated formatting over configurable rules:** ESLint's 100+ formatting rules still left room for team disagreement and couldn't handle dynamic JavaScript patterns like inline callback arguments. Prettier eliminates debate by accepting only one meaningful parameter — print width — and producing identical output regardless of how the original code was written, removing style decisions entirely from code review. - **Prettier ignore as the escape valve:** When teams resist adopting Prettier due to intentional formatting choices — such as aligned equals signs in enums — the practical response is to use `// prettier-ignore` comments above those specific blocks. Long estimates only 0.1% of a typical codebase genuinely warrants manual formatting exceptions, making blanket resistance to automation statistically unjustified. - **Never run Prettier through ESLint:** Using the ESLint-Prettier plugin routes formatting through ESLint's rule engine, which reruns fixers up to 10 times when fixes conflict, turning a sub-second formatting operation into a multi-second delay per save. Running Prettier directly as a separate process avoids this overhead entirely and keeps the two tools' responsibilities cleanly separated. - **Unified AST toolchains solve the real performance problem:** Tools like Biome and OXC format are faster not solely because they use Rust, but because they parse JavaScript once and pass a single AST through formatting, linting, and analysis sequentially. The traditional stack parses and regenerates code at each tool boundary, multiplying overhead — a structural inefficiency that a Rust rewrite alone would not fix. - **Open source financial sustainability gap:** Prettier has raised approximately $243,000 total across nine-plus years on OpenCollective, with no full-time maintainers and no backing company. Long frames this as the standard open source trajectory: initial creative energy drives adoption, but long-term maintenance requires compensation structures that donation models rarely provide at sufficient scale for tools used by millions of developers daily. → NOTABLE MOMENT Long revealed that the productivity benefit Prettier became most known for — writing messy code and reformatting it instantly with one keystroke — was never the original design goal. He built it to eliminate PR review arguments, and the authoring speed improvement emerged as an entirely unplanned side effect after release. 💼 SPONSORS [{"name": "Unblocked", "url": "https://getunblocked.com/sedaily"}, {"name": "GuardSquare", "url": "https://www.guardsquare.com"}] 🏷️ JavaScript Tooling, Code Formatting, Open Source Sustainability, AST Parsing, Developer Experience
