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    • Debugging basics and error handling JavaScript

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    Question 1

    Which of the following is the correct way to log a variable in JavaScript?

    • A

      debug(x);


    • B

      console.print(x);

    • C

      log(x);

    • D

      console.log(x);

    Question 2

    What kind of error is this?

    JavaScript 
    console.log("Hello);


    • A

      Runtime Error

    • B

      Syntax Error

    • C

      Logical Error

    • D

      Reference Error

    Question 3

    What will the following code log?

    JavaScript 
    let x = 0;
if (x = 10) {
  console.log("x is 10");
}


    • A

      SyntaxError

    • B

      "x is 10"

    • C

      Nothing

    • D

      ReferenceError

    Question 4

    What will the following code output?

    JavaScript 
    let name;
console.log(name.length);


    • A

      undefined

    • B

      0

    • C

      TypeError

    • D

      NaN

    Question 5

    What is the output of this code?

    JavaScript 
    try {
  throw new Error("Something went wrong");
} catch (e) {
  console.log(e.message);
}


    • A

      Error

    • B

      false

    • C

      undefined

    • D

      Something went wrong

    Question 6

    What does the finally block do in a try-catch-finally structure?


    • A

      Always runs

    • B

      Runs only if catch executes

    • C

      Only runs if there's an error

    • D

      Only runs if no error occurs

    Question 7

    Which is a common mistake with switch-case statements in JS?

    • A

      Using var inside case

    • B

      Forgetting default

    • C

      Using == instead of ===

    • D

      Using numbers in cases

    Question 8

    How can you avoid floating point precision errors in JavaScript?

    • A

      Round every result

    • B

      Multiply and divide integers

    • C

      Use BigInt

    • D

      Avoid using decimals

    Question 9

    What is wrong with the following code?

    JavaScript 
    let obj = {};
if (obj === null && typeof obj !== "undefined") {
  console.log("Valid");
}


    • A

      Nothing

    • B

      obj is null

    • C

      Order of conditions is incorrect

    • D

      obj is undefined

    Question 10

    What is the output?

    JavaScript 
    try {
  console.log("try");
} catch (e) {
  console.log("catch");
} finally {
  console.log("finally");
}


    • A

      try

    • B

      try finally

    • C

      catch

    • D

      finally only

    There are 10 questions to complete.

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