add hw2

node_modules/ramda/es/lens.js

@@ -0,0 +1,39 @@
+import _curry2 from "./internal/_curry2.js";
+import map from "./map.js";
+/**
+ * Returns a lens for the given getter and setter functions. The getter "gets"
+ * the value of the focus; the setter "sets" the value of the focus. The setter
+ * should not mutate the data structure.
+ *
+ * @func
+ * @memberOf R
+ * @since v0.8.0
+ * @category Object
+ * @typedefn Lens s a = Functor f => (a -> f a) -> s -> f s
+ * @sig (s -> a) -> ((a, s) -> s) -> Lens s a
+ * @param {Function} getter
+ * @param {Function} setter
+ * @return {Lens}
+ * @see R.view, R.set, R.over, R.lensIndex, R.lensProp
+ * @example
+ *
+ *      const xLens = R.lens(R.prop('x'), R.assoc('x'));
+ *
+ *      R.view(xLens, {x: 1, y: 2});            //=> 1
+ *      R.set(xLens, 4, {x: 1, y: 2});          //=> {x: 4, y: 2}
+ *      R.over(xLens, R.negate, {x: 1, y: 2});  //=> {x: -1, y: 2}
+ */
+
+var lens =
+/*#__PURE__*/
+_curry2(function lens(getter, setter) {
+  return function (toFunctorFn) {
+    return function (target) {
+      return map(function (focus) {
+        return setter(focus, target);
+      }, toFunctorFn(getter(target)));
+    };
+  };
+});
+
+export default lens;