performance - Does using JavaScript regexp literals in loops consume unnecessary memory? -

for example:

for (var idx = 0, len = lines.length; idx < len; idx += 1) {   /^regexp?/i.test(lines[idx]); } 

would following more efficient?

var pattern = /^regexp?/i; (var idx = 0, len = lines.length; idx < len; idx += 1) {   pattern.test(lines[idx]); } 

my understanding new regexp object created each iteration in first case, consuming more memory necessary. understanding correct, or javascript engines perform optimizations make examples above equivalent?

the cached regex will faster. more elements in lines, more time waste re-creating same regex object.