javascriptNull / UndefinedHard

Greeting says "hi null" instead of "hi guest"

Time: 0:00

BugFind the bug and fix the code

What it should do

greet(user) greets the user by name, or as "guest" when there is no name. Example: greet({ name: null }) → "hi guest".

What happens instead

greet({ name: null }) returns "hi null". greet({}) works.

function greet(user) {
    const { name = "guest" } = user;
    return "hi " + name;
}

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

⏱️0:00

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Hint 3

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This bug belongs to the null and undefined errors pattern

Cannot read properties of undefined, NoneType has no attribute, NaN appearing from nowhere.

Learn the null and undefined errors pattern Step through your own code

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javascriptNull / UndefinedHard

Greeting says "hi null" instead of "hi guest"

Time: 0:00

BugFind the bug and fix the code

What it should do

greet(user) greets the user by name, or as "guest" when there is no name. Example: greet({ name: null }) → "hi guest".

What happens instead

greet({ name: null }) returns "hi null". greet({}) works.

function greet(user) {
    const { name = "guest" } = user;
    return "hi " + name;
}

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

⏱️0:00

Hints

🏆 0 hints = Flawless Solve

Think & Test Cooldown

2:00 remaining

Take a moment to read the bug symptom and trace the code with Run & Check before unlocking Hint 1.

Hint 2

Unlocks after Hint 1

Hint 3

Unlocks after Hint 2

This bug belongs to the null and undefined errors pattern

Cannot read properties of undefined, NoneType has no attribute, NaN appearing from nowhere.

Learn the null and undefined errors pattern Step through your own code

Greeting says "hi null" instead of "hi guest"

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What happens instead

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Greeting says "hi null" instead of "hi guest"

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What happens instead

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