The replacement of _.trimStart(toTest, '://') with toTest.replace('://', '') might not be equivalent in all cases. trimStart removes all leading occurrences of the specified characters, while replace only replaces the first occurrence. Consider using toTest.substring(3) instead for a more direct replacement.

This is equivalent. We already know that :// is always at the start (that's what .startsWith(://) for). So, it will always replace the leading one.

Also, unlike .slice(3), .replace() prevents string CoW inside Node.js v8, which helps release memory pressure by allowing old strings to be GCed from the memory (.slice() holds the reference of the original string, preventing that from being GCed).

The replacement of _.isEmpty(filtered[i]) with filtered[i].length === 0 might not handle undefined or null values correctly. Consider using !filtered[i] || filtered[i].length === 0 to maintain the same behavior as lodash's isEmpty.

This is not necessary. We already know that the filtered is string[], so filtered[i] will never be nullish.

The replacement of _.isEmpty(_.trim(ruleText)) with ruleText.trim().length === 0 might throw an error if ruleText is undefined or null. Consider using a null check: !ruleText || ruleText.trim().length === 0.

We already know that ruleText is a string and will never be falsy.