正则表达式总共不能超过3个字母

Question

正则表达式不能同时包含3个以上的字母（即“ Joe4u”可以，但“ JoeL4u”不可以）我一直在尝试几种方法，但是似乎都不可行，我已经尝试了Lookahead和Lookbehind，但没有任何这只是一个我做了几次尝试

^(?=[A-Za-z]*[A-Za-z]{0,2}[^A-Za-z]*)(?=.{8,})

Answer 1

Just use ! to reverse the test

if (!/[a-zA-Z]{4}/.test(str)) {
  ...
}

How this works step by step

• /[a-zA-Z]{4}/.test(str) checks if the string contains four consecutive letters
• !... reverses the result

Answer 2

This LIF_HKN 's answer, thanks to him for the help

^([A-Za-z]{0,3}[^A-Za-z]+)*[A-Za-z]{0,3}$

You can play with it here Debuggex Demo