javascript Regex question mark (?) not detect

Question

Hi all I tried to create some regex with random value.

var data = "demo purpose?";  **OR**  var data = "demo purpose";
var sentence = "can I put these app as demo purpose?";
var re = new RegExp("\b(" + data + ")\b", "g");
console.log(sentence.match(re));   // output ["demo purpose"]

In variable data have two different value demo purpose? & demo purpose with only question mark. Both console out are same please any one Give me hint what should i do in these case.

- Thank you

Answer 1

you need to escape ? (i.e. write \?) or else it would be interpreted as a quantifier in regex.

Furthermore, the \b is not really necessary because it tries to match a non blank char in which case there is nothing behind demo purpose? so sentence.match(new RegExp("\b(demo purpose\?)\b", "g")) would return null.

If you want randomness, use Math.random. Make an array and get an random integer or 0 or 1 (with Math.floor) as the index.