Homework

• Use const price = 1500 and const gstRate = 18.
• Compute GST amount and total (price + GST). Do not wrap this in a function — plain top-level variables and expressions.
• Log price, GST amount, and total.

const price = 1500;
const gstRate = 18;
const gstAmount = (price * gstRate) / 100;
const total = price + gstAmount;

console.log("Price:", price);
console.log("GST Amount:", gstAmount);
console.log("Total Amount:", total);

Reference: ../js/day3.js. Run with node day3.js from day-3/js.

• Compare 10 different value pairs with both == and === (log each pair).
• In a block comment, draw a small table summarising which pairs differ between == and === and why (coercion vs strict types).

/*
| # | Expression A   | Expression B | ==    | ===   | Why (short)                          |
|---|----------------|--------------|-------|-------|--------------------------------------|
| 1 | 5              | "5"          | true  | false | == converts string to number         |
| 2 | true           | 1            | true  | false | == converts boolean to number        |
| 3 | false          | 0            | true  | false | ==: false → 0                        |
| 4 | null           | undefined    | true  | false | == special case; types differ        |
| 5 | ""             | 0            | true  | false | ==: both treated as “falsy number”   |
| 6 | " "            | 0            | true  | false | ==: string trims/coerces to number   |
| 7 | []             | false        | true  | false | ==: [] → "" → 0                      |
| 8 | [1]            | 1            | true  | false | ==: array coerced to primitive       |
| 9 | 0              | false        | true  | false | ==: false → 0                        |
|10 | "10"           | 10           | true  | false | ==: string "10" → number 10          |
|   |                |              |       |       | === never coerces — types must match |
*/
console.log(5 == "5", 5 === "5");
console.log(true == 1, true === 1);
console.log(false == 0, false === 0);
console.log(null == undefined, null === undefined);
console.log("" == 0, "" === 0);
console.log(" " == 0, " " === 0);
console.log([] == false, [] === false);
console.log([1] == 1, [1] === 1);
console.log(0 == false, 0 === false);
console.log("10" == 10, "10" === 10);

Full table + all ten pairs: ../js/day3.js.

• Write a ternary: age >= 18 ? "adult" : "minor".
• Test with five different ages (five separate console.log lines).

console.log(10, "→", 10 >= 18 ? "adult" : "minor");
console.log(17, "→", 17 >= 18 ? "adult" : "minor");
console.log(18, "→", 18 >= 18 ? "adult" : "minor");
console.log(25, "→", 25 >= 18 ? "adult" : "minor");
console.log(65, "→", 65 >= 18 ? "adult" : "minor");

Reference: ../js/day3.js.

• If the user is a member and purchase total > 1000, apply a 10% discount; otherwise discount is 0.
• Use && together with a ternary (no separate function required).
• Log discount and final amount. Try at least: member + high total, member + low total, non-member + high total.

let isMember = true;
let purchaseTotal = 1500;
let discount = isMember && purchaseTotal > 1000 ? purchaseTotal * 0.1 : 0;
let finalAmount = purchaseTotal - discount;
console.log("Case A → discount:", discount, "final:", finalAmount);

isMember = true;
purchaseTotal = 800;
discount = isMember && purchaseTotal > 1000 ? purchaseTotal * 0.1 : 0;
finalAmount = purchaseTotal - discount;
console.log("Case B → discount:", discount, "final:", finalAmount);

isMember = false;
purchaseTotal = 1500;
discount = isMember && purchaseTotal > 1000 ? purchaseTotal * 0.1 : 0;
finalAmount = purchaseTotal - discount;
console.log("Case C → discount:", discount, "final:", finalAmount);

Reference: ../js/day3.js.