Assignment

Complete these exercises after the session. All exercises use the tea data.

import { teas } from "../data/teas.js";

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Exercise 1: Rewrite with Array Methods

This code uses a traditional for-loop. Rewrite it using filter and map with arrow functions:

const result = [];
for (let i = 0; i < teas.length; i++) {
  if (teas[i].caffeineLevel !== "none") {
    result.push(teas[i].name.toUpperCase());
  }
}
console.log(result);

Your solution should be 2-3 lines using chained array methods.

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Exercise 2: Inventory Report ⭐

Build a function that generates an inventory report:

function inventoryReport(teas) {
  return {
    totalTeas: /* total number of teas */,
    inStock: /* number of teas where inStock is true */,
    outOfStock: /* number of teas where inStock is false */,
    totalInventoryValue: /* sum of (pricePerGram * stockCount) for all teas */,
    averagePrice: /* average pricePerGram across all teas */
  };
}

console.log(inventoryReport(teas));

Expected output structure:

{
  totalTeas: 20,
  inStock: 18,
  outOfStock: 2,
  totalInventoryValue: 234.55,  // example number
  averagePrice: 0.21           // example number
}

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Exercise 3: Low Stock Alert

Create a function that returns teas with low stock (less than 50 items):

function lowStockAlert(teas) {
  // Return array of objects with name and stockCount
  // sorted by stockCount (lowest first)
}

console.log(lowStockAlert(teas));

Expected output format:

[
  { name: "Silver Needle", stockCount: 25 },
  { name: "Matcha", stockCount: 30 },
  // ...
];

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Exercise 4: Teas by Origin ⭐⭐

Create a function that groups teas by their origin country:

function teasByOrigin(teas) {
  // Return object where keys are origins and values are arrays of tea names
}

console.log(teasByOrigin(teas));

Expected output format:

{
  Japan: ["Sencha", "Matcha", "Gyokuro", "Genmaicha"],
  India: ["Earl Grey", "Darjeeling", "Assam"],
  China: ["Dragon Well", "White Peony", ...],
  // ...
}

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Exercise 5: Search Function

Create a search function for the tea shop:

function searchTeas(teas, query) {
  // Return teas where the name contains the query (case-insensitive)
  // Return just the names, sorted alphabetically
}

console.log(searchTeas(teas, "earl"));
// Returns: ["Earl Grey"]

console.log(searchTeas(teas, "dragon"));
// Returns: ["Dragon Well"]

console.log(searchTeas(teas, "ch"));
// Returns: ["English Breakfast", "Genmaicha", "Lapsang Souchong"]

Hint: Use .toLowerCase() and .includes() for case-insensitive search.

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Optional: reduce

These exercises use reduce. Try them if you want a challenge!

Exercise 6: Total Inventory Value (Optional)

Calculate the total value of all tea inventory using reduce:

const totalValue = teas.reduce((sum, tea) => {
  // add pricePerGram * stockCount to sum
}, 0);

console.log("Total inventory value:", totalValue);

Hint: reduce builds up a single value by processing each item. The 0 is your starting value.

Exercise 7: Count by Type (Optional)

Use reduce to count how many teas of each type exist:

const countByType = teas.reduce((counts, tea) => {
  // increment counts[tea.type]
}, {});

console.log(countByType);
// Expected: { green: 6, black: 6, herbal: 4, oolong: 2, white: 2 }

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Submission

Create a folder week1-assignment/ with:

• exercise1.js - Rewrite with array methods

• exercise2.js - Inventory report

• exercise3.js - Low stock alert

• exercise4.js - Teas by origin

• exercise5.js - Search function

• exercise6.js - Total inventory value (optional)

• exercise7.js - Count by type (optional)

Each file should be runnable with node exerciseN.js.

// Example structure for exercise1.js
import { teas } from "../data/teas.js";

const result = teas.filter(/* ... */).map(/* ... */);

console.log(result);