When does the \'&& foo()\' operator actually call the \'foo()\' function?

Understanding "&& foo()" Operator

The "&&" operator, also known as "logical AND," often appears in code like "x && foo()". While this construct resembles the "if(x) { foo(); }" block, their functionalities are subtly different.

Shortcut Evaluation

Both "&&" (AND) and "||" (OR) operators have a unique characteristic known as "shortcut evaluation." This feature allows the operators to skip evaluating the second expression if the first expression already determines the outcome of the entire statement.

In the case of "&&", it only evaluates "foo()" if the value of "x" is truthy. If "x" is falsy, "foo()" is not executed since the result of the entire statement is already determined as falsy.

Conversely, in "||" statements, if the first expression is truthy, the second expression is not executed. The entire statement evaluates to true regardless, rendering the second expression irrelevant.

Precautions

However, when using shortcut evaluation, it's important to be aware of cases where variables may evaluate as unexpected values. For example, "0" evaluates as falsy, even though it's a defined variable.

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