匹配正则表达式的正则表达式

Question

I want to check with JavaScript & Regex that a test only validates any kind of string between pipes |

So these will test true

`word|a phrase|word with number 1|word with symbol?`
`word|another word`

But any of these will say false

`|word`
`word|`
`word|another|`
`word`

I have tried this

const string = 'word|another word|'
// Trying to exclude pipe from beginning and end only
const expresion = /[^\|](.*?)(\|)(.*?)*[^$/|]/g
// But this test only gives false for the first pipe at the end not the second
console.log(expresion.test(string))

Answer 1

The pattern [^\\|](.*?)(\\|)(.*?)*[^$/|] matches at least a single | but the . can match any character, and can also match another |

Note that this part [^$/|] mean any char except $ / |

---

You can start the match matching any character except a | or a newline.

Then repeat at least 1 or more times matching a | followed by again any character except a |

^[^|\r\n]+(?:\|[^|\r\n]+)+$

Explanation

• ^ Start of string
• [^|\\r\\n]+ Negated character class, match 1+ times any char except | or a newline
• (?: Non capture group
  • \\|[^|\\r\\n]+ Match | followed by 1+ times any char except a |or newline
• )+ Close group and repeat 1+ times to match at least a single pipe
• $ End of string

REgex demo

 const pattern = /^[^|\\r\\n]+(?:\\|[^|\\r\\n]+)+$/; [ "word|a phrase|word with number 1|word with symbol?", "word|another word", "|word", "word|", "word|another|", "word" ].forEach(s => console.log(`${pattern.test(s)} => ${s}`));

If there will be no newlines present, you can use:

^[^|]+(?:\|[^|]+)+$