fixed invert function,answered questions and added tests to check it works as expected

Author: asaniDev

Sprint-2/interpret/invert.js

@@ -9,21 +9,54 @@
 function invert(obj) {
   const invertedObj = {};
 
-  for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
+  if (Object.prototype.toString.call(obj) === "[object Object]") {
+    for (const [key, value] of Object.entries(obj)) {
+      invertedObj[value] = key;
+    }
+  } else {
+    throw new Error("error invalid input entered, expecting an object");
   }
 
   return invertedObj;
 }
 
+module.exports = invert;
+
+console.log(
+  `the return value when invert is called with ${invert({
+    cars: { toyota: 2, bmw: 1, benz: 4 },
+  })}`
+);
+
+/*
+for (const property in obj) {
+      if (typeof obj[property] !== "string") {
+        throw new Error(
+          "error invalid input entered, expecting an object to have only strings as values"
+        );
+      } else {
+        
+      }
+    }
+
+*/
+
 // a) What is the current return value when invert is called with { a : 1 }
+//it returns a string describing the object.
 
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
+//it aso returns a string describing the object.
 
 // c) What is the target return value when invert is called with {a : 1, b: 2}
+//the target return value is {"1": "a", "2": "b"}.
 
 // c) What does Object.entries return? Why is it needed in this program?
+//it returns an array made up of arrays of the original objects key - value pairs.
+//it allows us to unpack the contents of the object into an array which can then be used to create the new object
 
 // d) Explain why the current return value is different from the target output
+//because we used dot notation to assign a value to our key, this creates a property called key
+//and assigns it a value. we want our key to get its name from a variable so we need to use bracket notation.
 
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)
+//we can fix it by using invertedObj[value] = key.

Sprint-2/interpret/invert.test.js

@@ -0,0 +1,31 @@
+const invert = require("./invert.js");
+
+describe("tests to see if invert function swaps around the keys and values in a given object", () => {
+  test("if invert is passed a value which is not an object, it should throw an error", () => {
+    expect(() =>
+      invert([
+        ["x", 10],
+        ["y", 20],
+      ])
+    ).toThrow("error invalid input entered, expecting an object");
+  });
+
+  test("if we are passed an empty object we should return an empty object", () => {
+    expect(invert({})).toEqual({});
+  });
+
+  test("given an object with key value pairs, it should swap the keys and values in the object", () => {
+    expect(invert({ x: 10, y: 20 })).toEqual({ 10: "x", 20: "y" });
+    expect(
+      invert({ city: "Birmingham", population: "345908", boroughs: "20" })
+    ).toEqual({ Birmingham: "city", 345908: "population", 20: "boroughs" });
+  });
+});
+
+/*
+test("if invert is passed an object which has an array or object as one of its values, it should throw an error", () => {
+    expect(() => invert({ cars: { toyota: 2, bmw: 1, benz: 4 } })).toThrow(
+      "error invalid input entered, expecting an object to have only strings as values"
+    );
+  });
+*/