Summary - Conditionals
Build a day-of-the-week app using if, switch and the ternary operator.
Summary of all conditional tools
In this group you learned four conditional tools:
- if: tests a single condition.
- else/else if: adds branches for when the condition is false or for new conditions.
- switch: branches on a variable's value; completed with
breakanddefault. - ternary: returns a value in one line with
condition ? a : b.
You also saw that === strict equality is safer than == loose equality. Now combine them!
Exercise Summary task 1 - grade chain
The grade variable is a number from 0 to 100. Write an if/else if/else chain: 90 and above is 'Excellent', 70-89 is 'Good', 50-69 is 'Average', below is 'Poor'. Log each branch with console.log.
Show example solution
let grade = 75;
if (grade >= 90) {
console.log("Excellent");
} else if (grade >= 70) {
console.log("Good");
} else if (grade >= 50) {
console.log("Average");
} else {
console.log("Poor");
}Exercise Summary task 2 - day name switch
The day variable is a number from 1 to 7 (day of the week). Use switch to log the day name: 1 'Monday', 2 'Tuesday', 3 'Wednesday'. For unknown values log 'Unknown'. Use break in each case and add a default branch.
Show example solution
let day = 2;
switch (day) {
case 1:
console.log("Monday");
break;
case 2:
console.log("Tuesday");
break;
case 3:
console.log("Wednesday");
break;
default:
console.log("Unknown");
}Test yourself
-
When one variable needs many branches by value, which tool fits best?
- switch statement
- Nested ternaries
- Several ifs with &&
- console.log
Show answer
switch statement — Correct. switch is designed for branching on a single variable's value and improves readability.
-
Match each tool to its role
- if
- Tests a single condition
- else if
- Multi-branch chain
- switch
- Branching on a single value
- ternary
- One-line conditional expression
-
Complete the switch statement
let grade = "A"; switch (____) { case "A": console.log("Excellent"); break; default: console.log("Other"); }Show answer
let grade = "A"; switch (grade) { case "A": console.log("Excellent"); break; default: console.log("Other"); }