Q
What does console.log() output when logging an undefined variable?

Answer & Solution

Answer: Option Option B
Solution:
When logging an undefined variable using console.log(), the output will be 'undefined'. This indicates that the variable has not been assigned a value or does not exist in the current scope. It is different from an empty string, null, or an error message, as 'undefined' is a specific value in JavaScript that represents the absence of a value for a variable. Logging undefined variables using console.log() is useful for debugging and identifying variables that need initialization or assignments in the code.
Related Questions on Average

What is the recommended approach for handling console logs in production code?

A). Disable all console logs in production code.

B). Include detailed console logs for all scenarios.

C). Use conditional logging and minimize excessive logging.

D). Log all errors and exceptions using console.error().

How can you include JavaScript expressions in console.log() messages?

A). By enclosing expressions in backticks (`) within the message string.

B). By using special symbols like %s and %d.

C). By wrapping expressions in square brackets [].

D). By assigning expressions to separate log methods.

How does console.log() handle logging objects with nested properties?

A). It prints only the top-level properties of the object.

B). It converts the object and all nested properties into string representations.

C). It displays an error message for objects with nested properties.

D). It ignores nested properties and logs the object structure only.

What is the purpose of using console.log() for debugging JavaScript code?

A). To optimize code execution.

B). To log errors and exceptions.

C). To display messages to users.

D). To track variables, values, and program flow.

How can you log messages with different log levels using console.log()?

A). By using conditional statements to differentiate log levels.

B). By passing a log level as an argument to console.log().

C). By using multiple console.log() methods with different names.

D). By including log level prefixes in the message strings.

Which statement accurately describes the behavior of console.log() in JavaScript?

A). It halts script execution until the log is displayed.

B). It continues script execution while logging to the console.

C). It executes in parallel with other statements in the script.

D). It pauses script execution while logging to the console.

What happens if you include console.log() statements inside a loop with a large number of iterations?

A). It has no impact on script performance.

B). It significantly slows down script execution.

C). It optimizes loop execution for faster processing.

D). It automatically optimizes console logging for loops.

How does console.log() impact the accessibility of a webpage?

A). It improves accessibility by providing interactive elements.

B). It has no impact on accessibility.

C). It may negatively impact accessibility for users with disabilities.

D). It optimizes page performance for accessibility features.

How can you format log messages using console.log() to include variable values or expressions?

A). By using special symbols like %s and %d in the message string.

B). By enclosing expressions in backticks (`) within the message.

C). By concatenating variables directly in the parentheses.

D). By assigning expressions to separate log methods.

How can you log multiple values or messages using console.log()?

A). By using separate console.log() statements for each value.

B). By concatenating values within the parentheses.

C). By using HTML tags in the message string.

D). By separating values with commas within the parentheses.