How to make javascript regex match all lines when piping file

user_7778012 0
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If I run my regex on the data as a string I have no issues my three lines get matched.

https://regex101.com/r/pHsTvV/1

const regex = /(?<email>((?:[a-z0-9!#$%&'*+\/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+\/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])))\s*\|\s*(?<name>([a-zA-Z]{2,}\s[a-zA-Z]{1,}'?-?[a-zA-Z]{2,}\s?([a-zA-Z]{1,})?))\s*\|\s*(?<address>.*)\s*\|\s*(?<country>(\w|\.|\s*){1,})\s*\|\s*(?<phone>(\d|-|\ |\+|\(|\)|\.|\/){7,})/gm;
const str = `john.doe@gmail.test| John Doe| 160 Boston Rd| Chelmsford MA 11824| United States| 00088782000
jane.doe@aol.test| Jane Doe| 8415 45th St| Lyons IL 60534| United States| 0005800000
alicia.random123@gmail.test| Alicia Random| BLK 8, City Point| No.58 Wing Shun Street| Tsuen Wan| Not in U.S.| +00092262000`;

const lines = str.split('\n')
lines.forEach(line => {
    const test = regex.exec(str)
    if (test && test.groups) {
        console.dir(test.groups)
    } else {
        console.log('could not match')
    }
});

However when I load my data from a txt file javascript always gives me one out of two lines not matched:

const regex = /(?<email>((?:[a-z0-9!#$%&'*+\/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+\/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])))\s*\|\s*(?<name>([a-zA-Z]{2,}\s[a-zA-Z]{1,}'?-?[a-zA-Z]{2,}\s?([a-zA-Z]{1,})?))\s*\|\s*(?<address>.*)\s*\|\s*(?<country>(\w|\.|\s*){1,})\s*\|\s*(?<phone>(\d|-|\ |\+|\(|\)|\.|\/){7,})/gm;
import * as fs from 'fs';
import * as path from 'path';
import * as es from 'event-stream';
const filePath = path.join(process.cwd(), 'data/test.txt')
var s = fs.createReadStream(filePath)
    .pipe(es.split())
    .pipe(es.mapSync(function (line: string) {
        let values = regex.exec(line.trim())
        if (values && values.groups) {
            console.dir(values.groups)
        } else {
            console.log(`COULD NOT MATCH`)
            console.log(line)
        }
    }).on('error', function (err) {
        console.log('Error while reading file.', err);
    })
        .on('end', function () {
            console.log('Read entire file.')
        })
    )

The test.txt file is as follows:

john.doe@gmail.test| John Doe| 160 Boston Rd| Chelmsford MA 11824| United States| 00088782000
jane.doe@aol.test| Jane Doe| 8415 45th St| Lyons IL 60534| United States| 0005800000
alicia.random123@gmail.test| Alicia Random| BLK 8, City Point| No.58 Wing Shun Street| Tsuen Wan| Not in U.S.| +00092262000

even on a file with 100 lines it is always one line out of two that do not get matched. When I read the file the jane.doe@aol.test does not get matched

I have tried the following to see if its line specific:

const regex = /(?<email>((?:[a-z0-9!#$%&'*+\/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+\/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])))\s*\|\s*(?<name>([a-zA-Z]{2,}\s[a-zA-Z]{1,}'?-?[a-zA-Z]{2,}\s?([a-zA-Z]{1,})?))\s*\|\s*(?<address>.*)\s*\|\s*(?<country>(\w|\.|\s*){1,})\s*\|\s*(?<phone>(\d|-|\ |\+|\(|\)|\.|\/){7,})/gm;
const uniqueStr = `jane.doe@aol.test| Jane Doe| 8415 45th St| Lyons IL 60534| United States| 0005800000`

const test = regex.exec(uniqueStr)
if (test && test.groups) {
    console.dir(test.groups)
} else {
    console.log('could not match')
    console.log(uniqueStr)
}

This does not match but if I try the regex on regex101 there are no matches issue.

https://regex101.com/r/52kpRD/1

pipe javascript regex
1 Answers

Look at the accepted answer of this question: RegExp is Stateful

Essentialy, your regex is an object that preserves the index in a line where it found the last match, and the next time it continues from there instead of looking for a match from the start of the line again.

So one solution is to manually reset regex.lastIndex with your every call to es.MapSync

like this:

let s = fs.createReadStream(filePath)
    .pipe(es.split())
    .pipe(es.mapSync(function (line) {
            regex.lastIndex = 0; //Reset the RegExp index
            let values = regex.exec(line.trim())
            if (values && values.groups) {
                console.dir(values.groups)
            } else {
                console.log(`COULD NOT MATCH`)
                console.log(line)
            }
        }).on('error', function (err) {
            console.log('Error while reading file.', err);
        })
            .on('end', function () {
                console.log('Read entire file.')
            })
    )

Mind you, this only happens because regex is defined globally. If you were to assign the regex inside the mapSync() callback it should have the same effect. However, resetting the lastIndex is simpler and probably more performant.

user_23289580
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