add hw2

node_modules/ramda/es/collectBy.js

@@ -0,0 +1,58 @@
+import _curry2 from "./internal/_curry2.js";
+import _reduce from "./internal/_reduce.js";
+/**
+ * Splits a list into sub-lists, based on the result of calling a key-returning function on each element,
+ * and grouping the results according to values returned.
+ *
+ * @func
+ * @memberOf R
+ * @since v0.28.0
+ * @category List
+ * @typedefn Idx = String | Int | Symbol
+ * @sig Idx a => (b -> a) -> [b] -> [[b]]
+ * @param {Function} fn Function :: a -> Idx
+ * @param {Array} list The array to group
+ * @return {Array}
+ *    An array of arrays where each sub-array contains items for which
+ *    the String-returning function has returned the same value.
+ * @see R.groupBy, R.partition
+ * @example
+ *      R.collectBy(R.prop('type'), [
+ *        {type: 'breakfast', item: '☕️'},
+ *        {type: 'lunch', item: '🌯'},
+ *        {type: 'dinner', item: '🍝'},
+ *        {type: 'breakfast', item: '🥐'},
+ *        {type: 'lunch', item: '🍕'}
+ *      ]);
+ *
+ *      // [ [ {type: 'breakfast', item: '☕️'},
+ *      //     {type: 'breakfast', item: '🥐'} ],
+ *      //   [ {type: 'lunch', item: '🌯'},
+ *      //     {type: 'lunch', item: '🍕'} ],
+ *      //   [ {type: 'dinner', item: '🍝'} ] ]
+ */
+
+var collectBy =
+/*#__PURE__*/
+_curry2(function collectBy(fn, list) {
+  var group = _reduce(function (o, x) {
+    var tag = fn(x);
+
+    if (o[tag] === undefined) {
+      o[tag] = [];
+    }
+
+    o[tag].push(x);
+    return o;
+  }, {}, list);
+
+  var newList = [];
+
+  for (var tag in group) {
+    newList.push(group[tag]);
+  }
+
+  return newList;
+});
+
+export default collectBy;