How do I remove all whitespaces except those between words with Regular Expression in Javascript

Question

  var str=" hello world! , this is Cecy ";
  var r1=/^\s|\s$/g;
  console.log(str.match(r1));
  console.log(str.replace(r1,''))

Here, the output I expect is "hello world!,this is Cecy", which means remove whitespaces in the beginning and the end of the string, and the whitespace before and after the non-word characters. The output I have right now is"hello world! , this is Cecy", I don't know who to remove the whitespace before and after "," while keep whitespace between "o" and "w" (and between other word characters).

p.s. I feel I can use group here, but don't know who

Answer 1

Method 1

See regex in use here

\B\s+|\s+\B

• \B Matches a location where \b doesn't match
• \s+ Matches one or more whitespace characters

const r = /\B\s+|\s+\B/g
const s = ` hello world! , this is Cecy `

console.log(s.replace(r, ''))

---

Method 2

See regex in use here.

(?!\b\s+\b)\s+

• (?!\b +\b) Negative lookahead ensuring what follows doesn't match
  • \b Assert position as a word boundary
  • \s+ Match any whitespace character one or more times
  • \b Assert position as a word boundary
• \s+ Match any whitespace character one or more times

const r = /(?!\b\s+\b)\s+/g
const s = ` hello world! , this is Cecy `

console.log(s.replace(r, ''))