TOML Parser for Node.js

If you haven't heard of TOML, well you're just missing out. Go check it out now. Back? Good.

TOML Spec Support

toml-node supports TOML v1.1.0, scoring 673/680 (99.0%) on the official toml-test compliance suite:

The 7 remaining failures are inherent JavaScript platform limitations shared by all JS TOML parsers:

• 1 valid test: 64-bit integer precision (Number can't represent values beyond Number.MAX_SAFE_INTEGER)
• 6 invalid tests: UTF-8 encoding validation (Node.js handles UTF-8 decoding at the engine level before the parser sees the data)

Feature Support

• Strings: basic, literal, multiline, all escape sequences (\uXXXX, \UXXXXXXXX, \xHH, \e)
• Integers: decimal, hexadecimal (0xDEADBEEF), octal (0o755), binary (0b11010110)
• Floats: decimal, scientific notation, inf, -inf, nan
• Booleans: true, false
• Dates/Times: offset date-time, local date-time, local date, local time; seconds optional
• Arrays: mixed types allowed
• Tables: standard, inline (with dotted/quoted keys, newlines, trailing commas), array of tables
• Keys: bare, quoted, dotted (fruit.apple.color = "red")
• Comments: # line comments

Installation

npm install toml

Requires Node.js 20 or later. Zero runtime dependencies.

Usage

const toml = require('toml');
const data = toml.parse(someTomlString);

toml.parse throws an exception on parse errors with line and column properties:

try {
  toml.parse(someBadToml);
} catch (e) {
  console.error(`Parsing error on line ${e.line}, column ${e.column}: ${e.message}`);
}

Date/Time Values

Offset date-times are returned as JavaScript Date objects. Local date-times, local dates, and local times are returned as strings since they have no timezone information and can't be losslessly represented as Date:

const data = toml.parse(`
odt = 1979-05-27T07:32:00Z       # Date object
ldt = 1979-05-27T07:32:00        # string: "1979-05-27T07:32:00"
ld  = 1979-05-27                  # string: "1979-05-27"
lt  = 07:32:00                    # string: "07:32:00"
`);

data.odt instanceof Date  // true
typeof data.ldt            // "string"
typeof data.ld             // "string"
typeof data.lt             // "string"

Special Float Values

inf and nan are returned as JavaScript Infinity and NaN:

const data = toml.parse(`
pos_inf = inf
neg_inf = -inf
not_a_number = nan
`);

data.pos_inf === Infinity   // true
data.neg_inf === -Infinity  // true
Number.isNaN(data.not_a_number) // true

Requiring .toml Files

You can use the toml-require package to require() your .toml files with Node.js.

Building & Testing

toml-node uses the Peggy parser generator (successor to PEG.js).

npm install
npm run build
npm test
npm run test:spec           # run toml-test compliance suite
npm run test:spec:failures  # show failure details

Changes to src/toml.pegjs require a rebuild with npm run build.

License

toml-node is licensed under the MIT license agreement. See the LICENSE file for more information.