Regular expression to match group of consecutive characters

Question

I need a JS expression to match a combination of /* characters

I have this now

/(\b\/*\b)g

but it does not work.

ETA: any string that has /* should match

so...

Hello NO MATCH
123 NO MATCH
/* HELLo MATCH
/*4534534 MATCH

You can use: `/\/\*/g` but you should add valid/invalid matches in question. — anubhava, Mar 21 '18 at 17:23
What exactly do you mean by "a combination of /* characters"? Please provide an example of your input and expected output/match. — CAustin, Mar 21 '18 at 17:24
just did. Any time the exact combo of forward slash followed by star is occutring, it will be a match — sarsnake, Mar 21 '18 at 17:25
Does the `/*` itself need to be included in the match, or do you only want the characters that follow it? — CAustin, Mar 21 '18 at 17:27
[It sure works in this demo](https://regex101.com/r/JzZD7h/1) — anubhava, Mar 21 '18 at 17:28

score 1 · Answer 1 · answered Mar 21 '18 at 17:31

Since you only want to detect if it contains something you don't have to use regex and can just use .includes("/*"):

function fits(str) {
  return str.includes("/*");
}

var test = [
  "Hello NO MATCH",
  "123 NO MATCH",
  "/* HELLo MATCH",
  "/*4534534 MATCH"
];

var result = test.map(str => fits(str));
console.log(result);

The fourth bird · Accepted Answer · 2018-03-21T18:47:51.603

You might use a positive lookahead and test if the string contains /*?

If so, match any character one or more times .+ from the beginning of the string ^ until the end of the string $

^(?=.*\/\*).+$

Explanation

^ Begin of the string
(?= Positive lookahead that asserts what is on the right
- .*\/\* Match any character zero or more time and then /*
) Close positive lookahead
.+ Match any character one or more times
$ End of the string

const strings = [
  "Hello NO MATCH",
  "123 NO MATCH",
  "/* HELLo MATCH",
  "/*4534534 MATCH",
  "test(((*/*"
];
let pattern = /^(?=.*\/\*).+$/;

strings.forEach((s) => {
  console.log(s + " ==> " + pattern.test(s));
});

I think you could also use indexOf() to get the index of the first occurence of /*. It will return -1 if the value is not found.

const strings = [
  "Hello NO MATCH",
  "123 NO MATCH",
  "/* HELLo MATCH",
  "/*4534534 MATCH",
  "test(((*/*test",
  "test /",
  "test *",
  "test /*",
  "/*"
];
let pattern = /^(?=.*\/\*).+$/;

strings.forEach((s) => {
  console.log(s + " ==> " + pattern.test(s));
  console.log(s + " ==> " + (s.indexOf("/*") !== -1));
});

Regular expression to match group of consecutive characters

2 Answers2