Generate .FIT files in the Browser/Node. Currently intented for Course-Files but could be extended to other types if desired.

API

Course Files

Basic example:

    const myCourse = new FITCourseFile('course name', 
	Date.now(), 
	120 /*duration*/, 
	[1,1], [10,10]  /* start/stop lat/log */
	10, 5 /* ascend/descend (optional) */
	);
    myCourse
	.point(stamp /*point timestamp*/, [1,1] /* lat/log*/)
	.point(stamp, [1,2])
	.point(stamp, [1,3], 50 /* altitude meters*/, 100 /* total distance */)
	.point(stamp, [1,4], 55, 150)
	.turn(stamp, [2,4], 'right' /*turn icon*/, "go right" /*turn text */, 200 /*total distance*/)
	.point(stamp, [2,5], 50, 250)
	.turn(stamp, [2,4], 'left');
    console.log(myCourse.finalize(stamp /* end time */));

For details see src/course.js

"Low" level API

    import { FITEncoder } from './encoder.js';
    // or include dist/fit-file-writer.js and just use the global object


    const encoder = new FITEncoder();
    // start file
    encoder.writeFileId({ type: 'course', time_created: now.getTime() });

    encoder.writeCourse({ name: 'My Course' });
    // FIT files may contain multiple laps
    // see src/mesg.js for possible values
    encoder.writeLap({ ... });
    encoder.writeRecord({ ... });
    ...

    // get result
    const result = encode.blob;

data types

• pass timestamps as normal Javascript milliseconds stamps

• they will be converted to FIT-style stamps (in seconds)

• Note: the FIT epoch starts at 1989-12-31T00:00 underflows will result in values > year 2058 when reading

• pass normal lat/long values FIT uses semicircles so some rounding errors may occur

• distance is in meters

License

Licensed under the MIT License (MIT)

Credits

Extracted as a lib from the fit-route project by Nick Hollway: https://gitlab.com/nwholloway/fit-route/-/tree/8467d5baf7d8955f0e931074972796824d582ce2