Salesforce JS-Dev-101 Exam - Topic 1 Question 16 Discussion

The correct answer is A.

JavaScript evaluates the expression from left to right:

true + 3 + '100' + null

Step 1:

true + 3

In numeric addition, true is converted to:

1

So:

true + 3

becomes:

1 + 3

Result:

4

Step 2:

4 + '100'

Because one operand is a string, JavaScript performs string concatenation instead of numeric addition.

So:

4 + '100'

becomes:

'4100'

Step 3:

'4100' + null

Again, because one operand is already a string, JavaScript converts null into the string:

'null'

So the final result is:

'4100null'

Execution summary:

true + 3 + '100' + null

// 1 + 3 + '100' + null

// 4 + '100' + null

// '4100' + null

// '4100null'

Therefore, the verified answer is A.