Lab solved

src/index.js

@@ -1,11 +1,73 @@
-// Entry
-class Entry {}
+// Entry 
+class Entry {
+    constructor(date, amount, description) {
+        this.date = date;
+        this.amount = amount;
+        this.description = description;
+    }
+}
+
+Entry.prototype.getFormattedAmount = function() {
+    return `${this.amount} €`;
+};
+
 
 // Income
-class Income {}
+
+class Income extends Entry {
+    constructor(date, amount, description) {
+        super(date, amount, description);
+        this.type = "income";
+    }
+}
 
 // Expense
-class Expense {}
+
+class Expense extends Entry {
+    constructor(date, amount, description, paid) {
+        super(date, amount, description);
+        this.paid = paid;
+        this.type = "expense";
+    }
+}
+Expense.prototype.getFormattedAmount = function() {
+    return `-${this.amount} €`;
+};
+
+
 
 // Budget
-class Budget {}
+class Budget {
+    constructor() {
+        this.entries = [];
+    }
+    addEntry(entry) {
+        this.entries.push(entry);
+    }
+    getCurrentBalance() {
+        let totalIncome = 0;
+        let totalExpenses = 0;
+
+        for (const entry of this.entries) {
+            if (entry.type === "income") {
+                totalIncome += entry.amount;
+            } else if (entry.type === "expense") {
+                totalExpenses += entry.amount;
+            }
+        }
+
+        return totalIncome -   totalExpenses;
+    }
+}
+
+// BONUS Get Formatted Entries
+
+Budget.prototype.getFormattedEntries = function() {
+    const formattedEntries = [];
+    this.entries.forEach(entry => {
+        formattedEntries.push(
+            `${entry.date} | ${entry.description} | ${entry.getFormattedAmount()}`
+        );
+    });
+    return formattedEntries;
+}