⚙️ TOML Formatter

Here is a TOML file that will not parse:

[package]
name = "my-app"
version=  "0.2.0"
edition="2021"
 [dependencies]
serde={ version = "1.0", features = ["derive"] }

See all four problems? Mixed spacing around =, an indent before [dependencies], an inline table wearing out its welcome, and a missing newline between the two tables. The formatter turns this into something a human would actually want to edit:

[package]
name = "my-app"
version = "0.2.0"
edition = "2021"

[dependencies]
serde = { version = "1.0", features = ["derive"] }

TOML's whole selling point is that a config file should be obviously correct just by glancing at it. When a hand-edited Cargo.toml or pyproject.toml drifts away from that, the formatter drags it back.

Gotcha that wastes the most time: dot-delimited keys versus section headers.

[tool]
pytest = "yes"        # declares table "tool" with key "pytest"

tool.pytest = "yes"   # declares flat key "tool.pytest" -- NOT the same

Both lines are valid. They define completely different data. If a [tool.pytest] section exists somewhere, flat-dot keys nearby create an ambiguous mess. The formatter does not restructure this for you -- but its validation pass flags duplicate or conflicting paths.

A few formatting decisions baked in:

• Inline tables stay inline up to a line-width threshold, then expand to multi-line. Comma position follows cargo fmt convention.
• Arrays of tables ([[bin]], [[test]]) get a blank line before each entry -- matches the convention used by Cargo, Poetry, and Maturin.
• Trailing commas inside inline tables are added (consistent diffs); trailing commas inside arrays are stripped (the TOML spec forbids them).
• Literal strings ('one\raw\path') are preferred over basic strings whenever no escape sequences appear. Paste a Windows path and the tool rewrites it as 'C:\Users\me\project' automatically.
• Datetime values (1979-05-27T07:32:00Z, 1979-05-27, 07:32:00) are recognized and left untouched. The tool never stringifies or rewrites them.

TOML is the configuration format for Cargo (Rust), pyproject.toml (Python), Hugo, uv, Taplo, and a growing list of others. If you switch between two of those ecosystems on the same day, a single normalizer keeps the spacing and table style consistent.