Returning the line of a searched text from a file using node.js

Question

I am using fs to read the contents of a file, and then searching for a particular word within that file, if the file contains that word instead of returning boolean or the word, I want the output the line that contains the keyword. How do I output that entire line?

const fs = require("fs");
let file = fs.readFileSync("read.txt", "utf8");
if(file.indexOf("keyword") >= 0) {
    console.log("Line of the keyword");
}

I only want the console.log() to output the line if that line contains the keyword.

Answer 1

I know you are just looking to log out your results but it may be interesting to see another approach which includes writing to a file as well as using a package designed to read files line-by-line. It may be helpful in the future.

linebyline npm package

const readline = require("linebyline");
const fs = require('fs');

const rl = readline('sample.txt');

rl.on('line', function (line, lineCount, byteCount) {

  console.log(lineCount);  // this is not zero-based

  // do something with the line of text
  // line = line.substr(3).substr(0, 9); or whatever

  if (line.includes("yourSearchTerm")) {
    fs.appendFileSync('modified.txt', lineCount + ":" + line + '\n');
    // or console.log(lineCount + ":" + line);
  }
});

rl.on('error', function(e) {
  // something went wrong
});