Regex from loops

Question

this.personRegex = (input) => {
            return new RegExp(persons.map((person) => {
                return person.fullname;
            }).join("|"), "gi");
        }

the above give me :

/lwe|alvin/gi;

How do I get the below:

/\b(?:lwe|alvin)\b/gi;

As the additional stuff does not seem to be related to the number of persons, simply do it in the code **Regex("\b(?:"+ map() + ")\b")**. — Tobi, Nov 24 '16 at 06:50
By adding `\b` to the beginning and end of the regexp you are creating? — , Nov 28 '16 at 05:46

score 1 · Accepted Answer · edited Nov 28 '16 at 06:31

1

personRegex = (persons) => {
    return new RegExp("\\b(?:"+persons.map((person, i) => {
        return person.fullname;
    }).join("|") + ")\\b", "gi");
}

console.log(personRegex([{
    fullname: "lwe"
}, {
    fullname: "alvin"
}]));

edited Nov 28 '16 at 06:31

answered Nov 24 '16 at 06:50

Mr.7

2,292
1
20
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knittl · Answer 2 · 2016-11-24T07:10:19.900

1

You can simply do string concatenation:

var personAlternatives = persons.map((person) => { return person.fullname; }).join("|")
this.personRegex = (input) => {
    return new RegExp('\\b(?:' + personAlternatives + ')\\b', "gi");
}

edited Nov 24 '16 at 07:10

answered Nov 24 '16 at 06:55

knittl

246,190
53
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364

Tobi · Answer 3 · 2016-11-28T06:53:11.083

1

This should give you the least overhead:

function buildRegex(array){
  var reg;
  var mapResult = array.map((item) => {
    return item.attr;
  }).join("|");
  return new RegExp("\\b(?:"+mapResult+")\\b", "gi");
}

console.log(buildRegex([{attr:"a"},{attr:"b"}]));

edited Nov 28 '16 at 06:53

answered Nov 24 '16 at 06:57

Tobi

525
4
7

What kind of overhead, compared to what? – Nov 28 '16 at 18:15

score 0 · Answer 4 · edited May 23 '17 at 12:24

You can use template strings, with String.raw to avoid worrying about double backslashes:

personRegex = input => 
  new RegExp(
    String.raw`\b(?:${input.map(person => person.fullname).join("|")})\b`,
    "gi");

console.log(personRegex([{fullname: 'Bob'}, {fullname: 'Sally'}]));

In the real world, you would want to escape any possible special regexp characters in the input. For more information on doing that, see this question.

Regex from loops

4 Answers4