Lately I've been facing an issue on JavaScript (node). Basically I have a string (which can be anything since it is inputted by a user) and I have to check:

1. If the string letters are all in lowercase;
2. If the string doesn't have any special characters (é-[ã*$, etc (that was just an example);
3. If the string has no numbers;
4. If the string, if it has more than one word, has only one blank/white space between all words. Nothing more, nothing less.

I know that might be too much, but I have no other option than ask for help since I'm not an expert on using RegEx.

PS: The closer I got was using this:

const regexPattern = string.match(/^[^a-z] $/) ? false : true;

But this only works for one word and that's it. If there's more than one word it will do nothing to the other words, and what I need is to check if every word and check if there is only one white space between them.

Thanks! I really appreciate it!

CodePudding user response：

_{This is a non regex solution}

You can split the string by a space and use Array.every to check whether every word in the string matches the regex.

Also, your regex should be /^[a-z] $/. Remove the ^, since it inverts the condition.

function validate(str){
  return str.split(" ").every(e => /^[a-z] $/.test(e))
}

console.log(validate("hello world"))
console.log(validate("hello"))
console.log(validate("hello  world"))

CodePudding user response：

Here is a working regex: /^([a-z] |([a-z] [a-z] ) )$/

const regexPattern = /^([a-z] |([a-z]  [a-z] ) )$/

console.log(regexPattern.test('this should work')) // true
console.log(regexPattern.test('thisshouldwork')) // true
console.log(regexPattern.test('this should not  work')) // false
console.log(regexPattern.test('thisshouldnotwork ')) // false
console.log(regexPattern.test('$% this should not work')) // false
console.log(regexPattern.test('  ')) // false