正则表达式以n的倍数匹配

Question

I want to match a string that starts with at least 4 spaces and in multiples of 4. So 4, 8, 12.

What i've got so far only matches at least 4 spaces.So it accepts 4, 5, 6...

/^[\s]{4,}\+/

Answer 1

Put the pattern which matches exactly four spaces inside a group and then make that group to repeat one or more times. And also you need to add a negative lookahead at the end, so that it won't match the string which has four spaces at the start followed by another space.

/^(?:\s{4})+(?! )/

DEMO

 var s = " I have four spaces" var s1 = " I have five spaces" alert(/^(?:\\s{4})+(?! )/.test(s)) alert(/^(?:\\s{4})+(?! )/.test(s1))