Function addLineNumbers

docs/tests/v2/es6/js/sanddance.js:3227–3238

* Prepends line numbers to each line of a string. * The line numbers will be left-padded with spaces to ensure an * aligned layout when rendered using monospace fonts. * @param {String} string - multi-line string to add line numbers to * @param {Number} start=1 - number of spaces to add * @para

(string)

function addLineNumbers(string) {
  var start = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 1;
  var delim = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : ': ';
  var lines = string.split(/\r?\n/);
  var maxDigits = String(lines.length + start - 1).length;
  return lines.map(function (line, i) {
    var lineNumber = i + start;
    var digits = String(lineNumber).length;
    var prefix = padLeft(lineNumber, maxDigits - digits);
    return prefix + delim + line;
  });
}
/**
 * Pads a string with a number of spaces (space characters) to the left
 * @param {String} string - string to pad