How to make Joi regex() validation fail if the string contains " " (whitespace)?

Question

I have the a vehicle registration number being validated by Joi in Node.js and need it to reject any string that contains whitespace (space, tab, etc.)

I tried the following schema, but Joi does let it go through:

  const schema = { 
    regNo: Joi.string()
     .regex(/^.*\S*.*$/)
     .required()
     .trim()
    }

So, if I submit "JOI 777" the string is considered valid.

What am I doing wrong? Thanks in advance,

Answer 1

This part of your regex -> /^.* is saying match anything, so the rest of your regEx is pretty much short circuited.

So your RegEx is a bit simpler, /^\S+$/

This is then saying, from the start to the end, everything has to be a None whitespace.. Also seen as this checks everything for whitespace, you could also take out your .trim()..

eg.

const tests = [
  "JOI 777",  //space in the middle
  "JOI777",   //looks good to me
  "  JOI777", //space at start
  "JOI777 ",  //space at end
  "JO\tI77",  //tab
  "ABC123",   //another one that seems ok.
  "XYZ\n111"  //newline
];

tests.forEach(t => {
  console.log(`${!!t.match(/^\S+$/)} "${t}"`);
});