A question about "if"
importance: 5
Which of these alerts are going to execute?
What will the results of the expressions be inside if(...)?
if (-1 || 0) alert( 'first' );
if (-1 && 0) alert( 'second' );
if (null || -1 && 1) alert( 'third' );The answer: the first and the third will execute.
Details:
// Runs.
// The result of -1 || 0 = -1, truthy
if (-1 || 0) alert( 'first' );
// Doesn't run
// -1 && 0 = 0, falsy
if (-1 && 0) alert( 'second' );
// Executes
// Operator && has a higher precedence than ||
// so -1 && 1 executes first, giving us the chain:
// null || -1 && 1 -> null || 1 -> 1
if (null || -1 && 1) alert( 'third' );