如果 Node.js 的最后一行中没有 \n，则检测新行

Question

I have data in buffer and I am processing it line by line.

In buf I have following data

name,email,phn
test1,test1@example.com,1234567890
test2,testt2@example.com,1234567891

The last line doesn't have new line so my loop is working only 2 times but it should work for 3 times because buf has 3 line of record

To detect line break I am using below script

   var stream = fs.createReadStream('file.txt', { flags: 'r', encoding: 'utf-8' });
     stream.on('data', async function (d) {
     buf += d.toString();
     var pos;
    while ((pos = buf.indexOf('\n')) >= 0) { 
    if (pos == 0) { 
     buf = buf.slice(1); // discard it
     continue; 
    }
    var line = buf.slice(0, pos).substr(0, buf.slice(0, pos).length);
    //processing logic
        }

Answer 1

The best way is to trim it (to make sure the ending newline is gone), then to split it on '\n' :

const lines = buf.trim().split("\n");

for (const line of lines) {
    console.log("found line:", line);
}

If you want to keep using indexOf for whatever reason, then just add a single '\n' to the end (trimming the string first to make sure you don't end up with two \n s):

buf = buf.trim() + "\n";