Convert MS Health weights JSON into CSV for Withings Healtmate

create-withings-weight-csv.js

#!/usr/bin/env node

const fs = require('fs');
const path = require('path');

const CHUNK_SIZE = 250;

const pad = n => n < 10 ? `0${n}` : n;

const formatDate = d => `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())} ${pad(d.getHours())}:${pad(d.getMinutes())}:${pad(d.getSeconds())}`;

function createWithingsWeightFiles(healthPath) {
	const destDir = path.dirname(healthPath);

	const health = JSON.parse(fs.readFileSync(healthPath));

	const csvEntries = health.all.entries.map((entry) => {
		const ts = parseInt(entry.EntryDateUtc.substring(6, entry.EntryDateUtc.length - 2));

		return `"${formatDate(new Date(ts))}",${entry.Value}`;
	});

	let csvHeader = 'Date,';

	if (health.useMetricWeight) {
		csvHeader += 'Weight';
	} else {
		csvHeader += '"Weight (lb)"';
	}

	for (let chunkNum = 0;; chunkNum++) {
		const chunk = csvEntries.slice(chunkNum * CHUNK_SIZE, (chunkNum + 1) * CHUNK_SIZE);
		if (chunk.length === 0) {
			break;
		}

		const csv = `${csvHeader}\n${chunk.join('\n')}`;

		fs.writeFileSync(path.join(destDir, `withings_weight_${chunkNum + 1}.csv`), csv);
	}
}

if (process.argv.length < 3) {
	throw new Error('Please specify MS Health JSON file')
}

createWithingsWeightFiles(process.argv[2]);