phpjs/experimental/strings/vfprintf.js

php.js offers community built php functions in javascript

function vfprintf(handle, format, args) {
  // http://kevin.vanzonneveld.net
  // +   original by: Brett Zamir
  // -    depends on: sprintf
  // -    depends on: fwrite
  // *     example 1: var fp = fopen('currency.txt', 'w');
  // *     example 1: vfprintf(fp, '%01.2f', [123.1]); // 123.10
  // *     returns 1: 6


  var str = this.sprintf.apply(this, [].concat(format, args));
  try {
    this.fwrite(handle, str);
  }
  catch (e) {
    throw new Error('Error in vfprintf() file-writing');
  }
  return str.length;
}