SQL

.gitignore

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-node_modules/
-.env
 .DS_Store
-.vscode/

courses/backend/advanced-javascript/week1-assignment /.gitignore

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+.DS_Store

courses/backend/advanced-javascript/week1-assignment /exercise1.js

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+import { teas } from "./teas.js";
+
+const result = teas
+  .filter((tea) => tea.caffeineLevel !== "none")
+  .map((tea) => tea.name.toUpperCase());
+
+console.log(result);

courses/backend/advanced-javascript/week1-assignment /exercise2.js

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+import { teas } from "./teas.js";
+function inventoryReport(teas) {
+  const totalTeas = teas.length;
+  const inStock = teas.filter((tea) => tea.inStock).length;
+
+  const outOfStock = teas.filter((tea) => !tea.inStock).length;
+
+  const totalInventoryValue = teas.reduce(
+    (sum, tea) => sum + tea.pricePerGram * tea.stockCount,
+    0,
+  );
+
+  const averagePrice =
+    teas.reduce((sum, tea) => sum + tea.pricePerGram, 0) / teas.length;
+  return {
+    totalTeas,
+    inStock,
+    outOfStock,
+    totalInventoryValue,
+    averagePrice,
+  };
+}
+console.log(inventoryReport(teas));

courses/backend/advanced-javascript/week1-assignment /exercise3.js

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+import { teas } from "./teas.js";
+function lowStockAlert(teas) {
+  return teas
+    .filter((tea) => tea.stockCount < 50)
+    .map((tea) => ({ name: tea.name, stockCount: tea.stockCount }))
+    .sort((a, b) => a.stockCount - b.stockCount);
+}
+console.log(lowStockAlert(teas));

courses/backend/advanced-javascript/week1-assignment /exercise4.js

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+import { teas } from "./teas.js";
+
+function teasByOrigin(teas) {
+  return teas.reduce((group, tea) => {
+    if (!group[tea.origin]) {
+      group[tea.origin] = [];
+    }
+
+    group[tea.origin].push(tea.name);
+
+    return group;
+  }, {});
+}
+
+console.log(teasByOrigin(teas));

courses/backend/advanced-javascript/week1-assignment /exercise5.js

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+import { teas } from "./teas.js";
+function searchTeas(teas, query) {
+  return teas
+    .filter((tea) => tea.name.toLowerCase().includes(query.toLowerCase()))
+    .map((tea) => tea.name)
+    .sort();
+}
+
+console.log(searchTeas(teas, "earl"));
+console.log(searchTeas(teas, "dragon"));
+console.log(searchTeas(teas, "ch"));

courses/backend/advanced-javascript/week1-assignment /exercise6.js

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+import { teas } from "./teas.js";
+const totalValue = teas.reduce((sum, tea) => {
+  return sum + tea.pricePerGram * tea.stockCount;
+}, 0);
+console.log("Total inventory value:", totalValue);

courses/backend/advanced-javascript/week1-assignment /exercise7.js

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+import { teas } from "./teas.js";
+const countByType = teas.reduce((counts, tea) => {
+  if (!counts[tea.type]) {
+    counts[tea.type] = 0;
+  }
+
+  counts[tea.type]++;
+
+  return counts;
+}, {});
+
+console.log(countByType);

courses/backend/advanced-javascript/week2-assignment/exercise1.js

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+import { teas } from "./teas.js";
+
+function stockByCaffeine(teas) {
+  return teas.reduce((acc, tea) => {
+    acc[tea.caffeineLevel] = (acc[tea.caffeineLevel] || 0) + tea.stockCount;
+    return acc;
+  }, {});
+}
+
+console.log(stockByCaffeine(teas));

courses/backend/advanced-javascript/week2-assignment/exercise2.js

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+import { teas } from "./teas.js";
+
+const order = {
+  id: 1001,
+  customerId: 42,
+  items: [
+    { teaId: 1, grams: 100 },
+    { teaId: 8, grams: 50 },
+    { teaId: 3, grams: 200 },
+  ],
+};
+//  Validate
+export function validateOrder(order, callback) {
+  setTimeout(() => {
+    const errors = order.items
+      .filter((item) => !teas.find((t) => t.id === item.teaId))
+      .map((item) => `Tea with id ${item.teaId} not found`);
+
+    callback({ valid: errors.length === 0, errors });
+  }, 200);
+}
+validateOrder(order, console.log);
+// Calculate total
+export function calculateTotal(order, callback) {
+  setTimeout(() => {
+    let total = 0;
+    for (const item of order.items) {
+      const tea = teas.find((t) => t.id === item.teaId);
+      if (tea) total += tea.pricePerGram * item.grams;
+    }
+
+    callback({ orderId: order.id, total });
+  }, 300);
+}
+calculateTotal(order, console.log);
+
+// Check stock
+export function checkStock(order, callback) {
+  setTimeout(() => {
+    const shortages = [];
+
+    for (const item of order.items) {
+      const tea = teas.find((t) => t.id === item.teaId);
+      if (tea && tea.stockCount < item.grams) {
+        shortages.push(`${tea.name} not enough stock`);
+      }
+    }
+
+    callback({
+      orderId: order.id,
+      inStock: shortages.length === 0,
+      shortages,
+    });
+  }, 400);
+}
+checkStock(order, console.log);

courses/backend/advanced-javascript/week2-assignment/exercise3.js

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+import { teas } from "./teas.js";
+
+import { validateOrder, calculateTotal, checkStock } from "./exercise2.js";
+
+const order = {
+  id: 1001,
+  customerId: 42,
+  items: [
+    { teaId: 1, grams: 100 },
+    { teaId: 8, grams: 50 },
+    { teaId: 3, grams: 200 },
+  ],
+};
+function processOrder(order) {
+  console.log("Processing order", order.id);
+
+  validateOrder(order, (validation) => {
+    if (!validation.valid) {
+      console.log("Validation failed:", validation.errors);
+      return;
+    }
+    console.log("Validation passed");
+
+    calculateTotal(order, (pricing) => {
+      console.log("Total:", pricing.total);
+
+      checkStock(order, (stock) => {
+        if (!stock.inStock) {
+          console.log("Stock issues:", stock.shortages);
+          return;
+        }
+
+        console.log("Order processed successfully!");
+      });
+    });
+  });
+}
+
+processOrder(order);

courses/backend/advanced-javascript/week2-assignment/exercise4.js

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+import { teas } from "./teas.js";
+
+import fs from "fs";
+
+function generateInventoryReport(callback) {
+  fs.readFile("./inventory-updates.json", "utf8", (err, data) => {
+    if (err) {
+      callback(err, null);
+      return;
+    }
+    const updates = JSON.parse(data);
+
+    const changes = updates.reduce((acc, update) => {
+      acc[update.teaId] = (acc[update.teaId] || 0) + update.change;
+      return acc;
+    }, {});
+
+    let report = "Inventory Report:\n";
+
+    teas.forEach((tea) => {
+      const change = changes[tea.id] || 0;
+      const newStock = tea.stockCount + change;
+
+      if (change !== 0) {
+        report += `- ${tea.name}: was ${tea.stockCount}, change ${change >= 0 ? "+" : ""}${change}, now ${newStock}`;
+        if (newStock < 0) report += " (NEGATIVE!)";
+        report += "\n";
+      }
+    });
+
+    callback(null, report);
+  });
+}
+
+generateInventoryReport((err, report) => {
+  if (err) {
+    console.error(err);
+    return;
+  }
+  console.log(report);
+});

courses/backend/advanced-javascript/week2-assignment/exercise5.js

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+import { teas } from "./teas.js";
+function runSequentially(tasks, finalCallback) {
+  let index = 0;
+
+  function next() {
+    if (index === tasks.length) {
+      finalCallback();
+      return;
+    }
+
+    const task = tasks[index];
+    index++;
+
+    task(() => next());
+  }
+
+  next();
+}
+
+// Test
+const tasks = [
+  (done) =>
+    setTimeout(() => {
+      console.log("Task 1");
+      done();
+    }, 300),
+  (done) =>
+    setTimeout(() => {
+      console.log("Task 2");
+      done();
+    }, 200),
+  (done) =>
+    setTimeout(() => {
+      console.log("Task 3");
+      done();
+    }, 100),
+];
+runSequentially(tasks, () => {
+  console.log("All tasks complete!");
+});

courses/backend/advanced-javascript/week2-assignment/inventory-updates.json

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+[
+  { "teaId": 1, "change": -20, "reason": "sale" },
+  { "teaId": 1, "change": 50, "reason": "restock" },
+  { "teaId": 8, "change": -10, "reason": "sale" },
+  { "teaId": 3, "change": -100, "reason": "sale" },
+  { "teaId": 8, "change": 30, "reason": "restock" }
+]