matches.js

const filters = {
	tamanho: 'G',
	cor: 'red'
};

const validkeys = ['tamanho','cor'];

const wheres = [];
const params = [];
const cases = [];

Object.keys(filters).forEach(key => {
	if (!validkeys.includes(key)) return;
	cases.push(`(CASE WHEN ${key} = ? THEN 1 ELSE 0 END) match_${key}`);
	params.push(filters[key]);
});

Object.keys(filters).forEach(key => {
	if (!validkeys.includes(key)) return;
	wheres.push(`${key} = ?`);
	params.push(filters[key]);
});

const result = await mysql.query(`
	SELECT id, ${cases.join(', ')}			
	FROM camisas
	WHERE ${wheres.join(' OR ')}
`, params);

const matches = result.rows.map(row => {
	let qtmatches = 0;
	
	Object.keys(filters).forEach(key => {
		if (!validkeys.includes(key)) return;
		qtmatches += row[`match_${key}`];
	});

	return qtmatches;
});

console.log(matches);
//  [2,1,0];