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Editing and explaining

Edits​

edit() crops an activity, splits or joins its laps, or splits it into several activities. Positions are durations from the original recording's start, so an edit always means the same thing, and editing an edited activity starts again from the original. The original is never changed.

import { readFileSync } from 'node:fs';
import { minutes, seconds } from '@pond-ts/fit';
import { readActivity } from '@pond-ts/fit/files';

const run = readActivity(readFileSync('interval-run.fit'));

const fixed = run.edit({
  crop: { from: minutes(2) },
  laps: { splitAt: [minutes(20)] },
});
console.log(
  run.stats().time.elapsed?.format(),
  '→',
  fixed.stats().time.elapsed?.format(),
);
console.log(run.laps.length, '→', fixed.laps.length);
console.log(fixed.original === run);
console.log(fixed.changes.map((c) => `${c.kind} at ${c.at.format()}`));
51:23 → 49:23
13 → 14
true
[ 'crop-start at 2:00', 'lap-split at 20:00' ]

parts splits one recording into several activities, a run and then the walk home. Each part is an activity of its own, with its clock starting at its own start. Its changes are only the ones that fall in it, with the part splits at its ends. A recording with no timestamps can have its laps edited, but can't be cropped or split into parts.

const split = run.edit({ parts: { splitAt: [minutes(30)] } });
console.log(split.parts.map((p) => p.stats().time.elapsed?.format()));
[ '30:00', '21:23' ]

Moving between the clocks​

An app keeps its own marks (a note, a custom segment) on the original recording, so they survive re-editing. fromOriginal puts a saved stretch on the edited activity's clock, cut to what was kept, or null when it was cropped off. toOriginal goes the other way.

const mark = { from: minutes(10), to: minutes(11) };
const onEdited = fixed.fromOriginal(mark)!;
console.log(onEdited.fromSeconds, onEdited.toSeconds);
const back = fixed.toOriginal(onEdited);
console.log(back.fromSeconds, back.toSeconds);
console.log(fixed.fromOriginal({ from: seconds(0), to: seconds(60) }));
480 540
600 660
null

Where a number comes from​

explain() says where one of an activity's numbers comes from: its source, how it is worked out, how much of the recording backs it, and the edits it went through.

const d = run.explain('distance');
console.log(d.source, d.coverage);
console.log(d.method);
console.log(run.explain('moving').source, run.explain('timer').source);
console.log(fixed.explain('distance').edits.length);
gps 1
Measured along the GPS line between fixes.
speed file
2