javascript - How to append to certain line of file?

Question

I want to append to a file but I want to start appending before </xml> tag end. appears. How can I do that?

var fs = require("fs");
fs.appendFile('somefile.xml', 'Content')

I have sth like this but it insert 'content' at the end of file, and I want it in specific line before specific 'keyword'

Answer 1

This might not be the easiest option, but at least it should get the job done. Haven't tested it, so it might require some changes. It reads the file and when it's done, it creates the new file by removing the </xml> tag, adding the content and then adding the </xml> tag again at the end.

var fs = require('fs');

var xmlFile;
fs.readFile('someFile.xml', function (err, data) {
  if (err) throw err;
  xmlFile = data;

  var newXmlFile = xmlFile.replace('</xml>', '') + 'Content' + '</xml>';

  fs.writeFile('someFile.xml', newXmlFile, function (err) {
    if (err) throw err;
    console.log('Done!');
  }); 
});