Added object solutions

SunJieMing · SunJieMing · commit 2f805ecd98ea · 2017-10-02T08:00:00.000-07:00
diff --git a/src/objects.js b/src/objects.js
@@ -1,38 +1,60 @@
 // Complete the following underscore functions.
 // Reference http://underscorejs.org/ for examples.
 
+/* eslint-disable no-unused-vars, arrow-body-style */
+
 const keys = (obj) => {
   // Retrieve all the names of the object's properties.
   // Return the keys as strings in an array.
   // Based on http://underscorejs.org/#keys
+  return Object.keys(obj);
 };
 
 const values = (obj) => {
   // Return all of the values of the object's own properties.
   // Ignore functions
   // http://underscorejs.org/#values
+  return Object.keys(obj).map((key) => {
+    return obj[key];
+  });
 };
 
 const mapObject = (obj, cb) => {
   // Like map for arrays, but for objects. Transform the value of each property in turn.
   // http://underscorejs.org/#mapObject
+  Object.keys(obj).forEach(key => (obj[key] = cb(obj[key])));
+  return obj;
 };
 
 const pairs = (obj) => {
   // Convert an object into a list of [key, value] pairs.
   // http://underscorejs.org/#pairs
+  return Object.keys(obj).map((key) => {
+    return [key, obj[key]];
+  });
 };
 
 const invert = (obj) => {
   // Returns a copy of the object where the keys have become the values and the values the keys.
   // Assume that all of the object's values will be unique and string serializable.
   // http://underscorejs.org/#invert
+  Object.keys(obj).forEach((key) => {
+    const newKey = obj[key];
+    obj[newKey] = key;
+    delete obj[key];
+  });
+  return obj;
 };
 
 const defaults = (obj, defaultProps) => {
   // Fill in undefined properties that match properties on the `defaultProps` parameter object.
   // Return `obj`.
   // http://underscorejs.org/#defaults
+  Object.keys(defaultProps).forEach((key) => {
+    if (Object.prototype.hasOwnProperty.call(obj, key)) return;
+    obj[key] = defaultProps[key];
+  });
+  return obj;
 };
 
 /* eslint-enable no-unused-vars */
