Replaces the value of the <base href="..."> in a HTML document.

replaceBaseHref.js

const fs = require('fs')

const args = process.argv.slice(2);
if (args.length < 2)
{
  console.log(`Replaces the value of the <base href="..."> in a HTML document.
  
USAGE:

  node replaceBaseHref.js <html-file> <new-value> [encoding]
  
  html-file - Path to the html file.
  new-value - The new value for the <base href="..."> tag.
  encoding  - Optional. Default is utf8.

EXAMPLE:

    node replaceBaseHref.js "index.html" "/myapp/" "utf8"
`);
  process.exit(1);
}

const fileToReplace = args[0];
const newValue = args[1];
const encoding = args[2] || 'utf8';

function exitWithError(error) {
  console.trace(error);
  process.exit(1);
}

fs.readFile(fileToReplace, encoding, function (error, data) {
  if (error)
    exitWithError(error);

  var newContent = data.replace(
    /<base\s+href\s*=\s*\"([^\"]*)"\s*>/g, 
    `<base href="${newValue}">`);

  fs.writeFile(fileToReplace, newContent, encoding, function (error) {
      if (error) exitWithError(error);
  });
});