feat: resolve get array element count

lib/averageSpeed.js

@@ -0,0 +1,12 @@
+/**
+  Calculate average speend with distance and time
+  @param {number} distance
+  @param {number} time
+  @returns {number} average speed
+*/
+
+function averageSpeed(distance, time) {
+  throw new Error("this method is still a skeleton");
+}
+
+module.exports = averageSpeed;

lib/getArrayElementCount.js

@@ -2,12 +2,38 @@
   Get count for all occurances of given element or array in an array
   If b is an array then it will count the occurrence of all elements in the given first array
   @param {array} a
-  @param {*} b
+  @param {array|number} b
   @returns {number} count value of element
 */
 
 function getArrayElementCount(a, b) {
-  throw new Error("this method is still a skeleton");
+  //throw new Error("this method is still a skeleton");
+  // Verify args types
+  if (!Array.isArray(a)) {
+    throw new Error("First argument should be an array");
+  }
+
+  if (typeof b !== "number" && !Array.isArray(b)) {
+    throw new Error("Second argument should be number");
+  }
+
+  a.forEach(element => {
+    if(typeof element !== "number") {
+      throw new Error("First argument should be an array");
+    }
+  });
+
+  if (Array.isArray(b)) {
+    b.forEach(element => {
+      if(typeof element !== "number") {
+        throw new Error("Second argument should be number");
+      }
+    });
+  }
+  var arr = Array.isArray(b) ? b : [ b ];
+
+  return arr.reduce((prev, curr) =>
+    prev += a.filter(element => element === curr).length, 0);
 }
 
 module.exports = getArrayElementCount;

test/averageSpeed.test.js

@@ -0,0 +1,19 @@
+const { averageSpeed } = require("../lib");
+
+describe("averageSpeed", () => {
+  it("should return averages", () => {
+    expect(averageSpeed(100, 1)).toEqual(100);
+    expect(averageSpeed(220, 2)).toEqual(110);
+    expect(averageSpeed(287, 3)).toBeCloseTo(95.666);
+  });
+
+  it("should throw error if first value is not a number", () => {
+    expect(() => averageSpeed("sdsds", 4)).toThrow("First argument should be a number");
+    expect(() => averageSpeed([1], 4)).toThrow("First argument should be a number");
+  });
+
+  it("should throw error if first value is not a number", () => {
+    expect(() => averageSpeed(100, false)).toThrow("Second argument should be a number");
+    expect(() => averageSpeed(100, "dss")).toThrow("Second argument should be a number");
+  });
+});

test/getArrayElementCount.test.js

@@ -11,12 +11,12 @@ describe("getArrayElementCount", () => {
   });
 
   it("should throw error if first arg is not array", () => {
-    expect(getArrayElementCount("sdsds", 4)).toThrow("First argument should be an array");
-    expect(getArrayElementCount(452755, 4)).toThrow("First argument should be an array");
+    expect(() => getArrayElementCount("sdsds", 4)).toThrow("First argument should be an array");
+    expect(() => getArrayElementCount(452755, 4)).toThrow("First argument should be an array");
   });
 
   it("should throw error if second arg is not present or is not a number or array", () => {
-    expect(getArrayElementCount([5, 7, 4, 6, 5, 4], false)).toThrow("Second argument should be number");
-    expect(getArrayElementCount([3, 4, 56, 5, 6], "dss")).toThrow("Second argument should be number");
+    expect(() => getArrayElementCount([5, 7, 4, 6, 5, 4], false)).toThrow("Second argument should be number");
+    expect(() => getArrayElementCount([3, 4, 56, 5, 6], "dss")).toThrow("Second argument should be number");
   });
 });