solved: reto mouredev#41

Author: matiasjaliff

app/src/main/java/com/mouredev/weeklychallenge2022/.gitignore

@@ -1 +1,3 @@
-node_modules
+node_modules
+package.json
+package-lock.json

app/src/main/java/com/mouredev/weeklychallenge2022/Challenge41.js

@@ -18,7 +18,25 @@
  */
 
 export function ohm(input) {
-  const errorMsg = "Invalid values";
-  if (typeof input !== "object" || Array.isArray(input)) return errorMsg;
-  else if (Object.keys(input).length !== 2) return errorMsg;
+  // input validation
+  const invalid =
+    typeof input !== "object" ||
+    Array.isArray(input) ||
+    Object.keys(input).length !== 2 ||
+    Object.keys(input).filter((key) => !["v", "r", "i"].includes(key)).length ||
+    Object.values(input).filter(
+      (value) => typeof value !== "number" || isNaN(value)
+    ).length;
+
+  if (invalid) return "Invalid values";
+
+  // calculation
+  const { v, r, i } = input;
+  const rounded = (num) => Math.round(num * 100) / 100;
+
+  return v === undefined
+    ? rounded(r * i)
+    : r === undefined
+    ? rounded(v / i)
+    : rounded(v / r);
 }

app/src/main/java/com/mouredev/weeklychallenge2022/Challenge41.test.js

@@ -1,25 +1,62 @@
 import { describe, it, expect } from "vitest";
 import { ohm } from "./Challenge41";
 
+const errorMsg = "Invalid values";
+
 describe("Reto #41 - LA LEY DE OHM", () => {
   it("ohm is a function", () => {
     expect(ohm).toBeTypeOf("function");
   });
 
   it("returns message 'Invalid values' if the provided parameter is not an object", () => {
-    expect(ohm({ v: 12, r: 220 })).not.toBe("Invalid values");
-    expect(ohm()).toBe("Invalid values");
-    expect(ohm(1, 2)).toBe("Invalid values");
-    expect(ohm([1, 2])).toBe("Invalid values");
-    expect(ohm("1, 2")).toBe("Invalid values");
+    expect(ohm({ v: 12, r: 220 })).not.toBe(errorMsg);
+    expect(ohm()).toBe(errorMsg);
+    expect(ohm(1, 2)).toBe(errorMsg);
+    expect(ohm([1, 2])).toBe(errorMsg);
+    expect(ohm("1, 2")).toBe(errorMsg);
   });
 
   it("returns message 'Invalid values' if the provided object has not two and only two properties", () => {
-    expect(ohm({ v: 12 })).toBe("Invalid values");
-    expect(ohm({ v: 12, r: 220 })).not.toBe("Invalid values");
-    expect(ohm({ v: 12, r: 220, i: 0.05 })).toBe("Invalid values");
-    expect(ohm({ v: 12, r: 220, i: 0.05, p: 0.82 })).toBe("Invalid values");
+    expect(ohm({ v: 12 })).toBe(errorMsg);
+    expect(ohm({ v: 12, r: 220 })).not.toBe(errorMsg);
+    expect(ohm({ v: 12, r: 220, i: 0.05 })).toBe(errorMsg);
+    expect(ohm({ v: 12, r: 220, i: 0.05, p: 0.82 })).toBe(errorMsg);
+  });
+
+  it("returns message 'Invalid values' if any of the keys of the provided objects is not recognized", () => {
+    expect(ohm({ v: 12, r: 220 })).not.toBe(errorMsg);
+    expect(ohm({ r: 220, i: 0.05 })).not.toBe(errorMsg);
+    expect(ohm({ v: 12, i: 0.05 })).not.toBe(errorMsg);
+    expect(ohm({ i: 0.05, v: 12 })).not.toBe(errorMsg);
+    expect(ohm({ v: 12, x: 220 })).toBe(errorMsg);
+    expect(ohm({ volt: 12, resistance: 220 })).toBe(errorMsg);
+  });
+
+  it("returns message 'Invalid values' if any of the values of the provided objects is not a number", () => {
+    expect(ohm({ v: 12, r: 220 })).not.toBe(errorMsg);
+    expect(ohm({ v: "1", r: 220 })).toBe(errorMsg);
+    expect(ohm({ v: 12, r: true })).toBe(errorMsg);
+    expect(ohm({ v: [1], r: 220 })).toBe(errorMsg);
+    expect(ohm({ v: 12, r: { value: 220 } })).toBe(errorMsg);
+    expect(ohm({ v: null, r: 220 })).toBe(errorMsg);
+    expect(ohm({ v: 12, r: NaN })).toBe(errorMsg);
   });
 
-  it.skip("returns message 'Invalid values' if the object provided has not the required shape", () => {});
+  it("returns a number", () => {
+    expect(ohm({ v: 12, r: 220 })).toBeTypeOf("number");
+  });
+
+  it("returns the result of the ohm's law", () => {
+    expect(ohm({ v: 12, r: 120 })).toBe(0.1);
+    expect(ohm({ v: 12, i: 0.1 })).toBe(120);
+    expect(ohm({ i: 0.1, r: 120 })).toBe(12);
+  });
+
+  it("the result is rounded to two decimal digits", () => {
+    expect(ohm({ v: 12, r: 120 })).toBe(0.1);
+    expect(ohm({ v: 12, r: 220 })).toBe(0.05);
+    expect(ohm({ v: 12, r: 220 })).not.toBe(12 / 220);
+    expect(ohm({ v: 12, i: 5.35 })).toBe(2.24);
+    expect(ohm({ v: 12, i: 5.35 })).not.toBe(12 / 5.35);
+  });
 });