Parse your .FIT files easily, directly from JS. Written in Typescript

$ npm install fit-file-parser --save

See in examples folder:

import fs from 'node:fs/promises'
import FitParser from 'fit-file-parser'

fs.readFile('./example.fit', (err, content) => {
  // Create a FitParser instance (options argument is optional)
  if (err) {
    console.error(err)
  }
  const fitParser = new FitParser({
    force: true,
    speedUnit: 'km/h',
    lengthUnit: 'km',
    temperatureUnit: 'kelvin',
    pressureUnit: 'bar', // accept bar, cbar and psi (default is bar)
    elapsedRecordField: true,
    mode: 'cascade',
  })

  // Parse your file
  fitParser.parse(content, (error, data) => {
    // Handle result of parse method
    if (error) {
      console.error(error)
    }
    else {
      console.log(JSON.stringify(data))
    }
  })
})

import fs from 'node:fs/promises'
import FitParser from 'fit-file-parser'

const buffer = await fs.readFile('./example.fit')
const fitObject = await fitParser.parseAsync(buffer)

To build the project, run:

npm run build

To run tests, run:

npm test

To rebuild the typescript types (as they are autogenerated from the FIT object) run:

this will update the file src/fit_types.ts as it is only running with node (with type stripping), regenerating them requires node>=245

To run the codegen in watch mode during local development, run:

To build the local examples, run:

npm run examples

To lint and format the code, run:

npm run lint

To run the typechecker, run:

npm run type-check

Needed to create a new instance. options is optional, and is used to customize the returned object.

Allowed properties :

• mode: String
  • cascade: Returned object is organized as a tree, eg. each lap contains a records fields, that is an array of its records (default)
  • list: Returned object is organized as lists of sessions, laps, records, etc..., without parent-child relation
  • both: A mix of the two other modes, eg. records are available inside the root field as well as inside each laps
• lengthUnit: String
  • m: Lengths are in meters (default)
  • km: Lengths are in kilometers
  • mi: Lengths are in miles
• temperatureUnit: String
  • celsius:Temperatures are in °C (default)
  • kelvin: Temperatures are in °K
  • fahrenheit: Temperatures are in °F
• speedUnit: String
  • m/s: Speeds are in meters per seconds (default)
  • km/h: Speeds are in kilometers per hour
  • mph: Speeds are in miles per hour
• force: Boolean
  • true: Continues even if they are errors (default for now)
  • false: Stops if an error occurs
• elapsedRecordField: Boolean
  • true: Includes elapsed_time, containing the elapsed time in seconds since the first record, and timer_time, containing the time shown on the device, inside each record field
  • false (default)

callback receives two arguments, the first as a error String, and the second as Object, result of parsing.

returns a Promise that resolves to the result of parsing.

All started thanks to Pierre Jacquier

Big thanks to Mikael Lofjärd for his early prototype. See CONTRIBUTORS.

MIT license; see LICENSE.

(c) 2019 Dimitrios Kanellopoulos