Test tests for matches and returns booleans while exec captures groups and matches the regex to the input.
If you only need to test an input string to match a regular expression, RegExp.test is most appropriate. It will give you a boolean return value which makes it ideal for conditions.
RegExp.exec gives you an array-like return value with all capture groups and matched indexes. Therefore, it is useful when you need to work with the captured groups or indexes after the match.
console.log(/^([a-z]+) ([A-Z]+)$/.exec("hello WORLD")) console.log(/^([a-z]+) ([A-Z]+)$/.test("hello WORLD"))
[ 'hello WORLD', 'hello', 'WORLD', index: 0, input: 'hello WORLD', groups: undefined ] true
Note that the first index in the array returned by exec is the complete matched string. The following indices are the individual groups captured by the regex.