thomasnorris · November 24, 2021 20:11
diff --git a/groupby.js b/groupby.js
 // returns grouping of arr by key
 let groupBy = function(arr, key) {
    return arr.reduce(function(rv, x) {
        (rv[x[key]] = rv[x[key]] || []).push(x);
        return rv;
    }, {});
 };
	// returns grouping of arr by key
	let groupBy = function(arr, key) {
	return arr.reduce(function(rv, x) {
	(rv[x[key]] = rv[x[key]] \|\| []).push(x);
	return rv;
	}, {});
	};