JavaScript Does using JavaScript regexp literals in loops consume unnecessary memory? does in javascript

For example:

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

Would the following be more efficient?

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

My understanding is that a new RegExp object would be created for each iteration in the first case, consuming more memory than is necessary. Is my understanding correct, or do JavaScript engines perform optimizations that make the examples above equivalent?

Answer:1

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

Answer:2

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