All tasks are done

Exercises/1-hoisting.js

@@ -1,5 +1,8 @@
 'use strict';
 
-const fn = null;
+const fn = () => {
+  const someData = undefined;
+  return someData;
+};
 
 module.exports = { fn };

Exercises/2-by-value.js

@@ -1,5 +1,10 @@
 'use strict';
 
-const inc = null;
+const inc = (n) => n + 1;
+
+const a = 5;
+const b = inc(a);
+
+console.log({ a, b });
 
 module.exports = { inc };

Exercises/3-by-reference.js

@@ -1,7 +1,13 @@
 'use strict';
 
+const obj = { n: 5 };
+
 const inc = (obj) => {
-  console.log(obj);
+  obj.n++;
 };
 
+inc(obj);
+
+console.dir(obj);
+
 module.exports = { inc };

Exercises/4-count-types.js

@@ -1,5 +1,15 @@
 'use strict';
 
-const countTypesInArray = null;
+//const arr = [true, 'hello', 5, 12, -200, false, false, 'word'];
+
+const countTypesInArray = (arr) => {
+  const conters = {};
+  for (const el of arr) {
+    const type = typeof el;
+    const count = conters[type] || 0;
+    conters[type] = count + 1;
+  }
+  return conters;
+};
 
 module.exports = { countTypesInArray };