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' );