voca/word_wrap.js

The ultimate JavaScript string library

'use strict';

require('./internal/is_nil.js');
var coerce_to_boolean = require('./internal/coerce_to_boolean.js');
require('./is_string.js');
var coerce_to_string = require('./internal/coerce_to_string.js');
var coerce_to_number = require('./internal/coerce_to_number.js');

var OPTION_WIDTH = 'width';
var OPTION_NEW_LINE = 'newLine';
var OPTION_INDENT = 'indent';
var OPTION_CUT = 'cut';
/**
 * Wraps `subject` to a given number of characters using a string break character.
 *
 * @function wordWrap
 * @static
 * @since 1.0.0
 * @memberOf Manipulate
 * @param  {string} [subject=''] The string to wrap.
 * @param  {Object} [options={}] The wrap options.
 * @param  {number} [options.width=75] The number of characters at which to wrap.
 * @param  {string} [options.newLine='\n'] The string to add at the end of line.
 * @param  {string} [options.indent='']  The string to intend the line.
 * @param  {boolean} [options.cut=false] When `false` (default) does not split the word even if word length is bigger than `width`. <br/>
 *                                       When `true` breaks the word that has length bigger than `width`.
 *
 * @return {string} Returns wrapped string.
 * @example
 * v.wordWrap('Hello world', {
 *   width: 5
 * });
 * // => 'Hello\nworld'
 *
 * v.wordWrap('Hello world', {
 *   width: 5,
 *   newLine: '<br/>',
 *   indent: '__'
 * });
 * // => '__Hello<br/>__world'
 *
 * v.wordWrap('Wonderful world', {
 *   width: 5,
 *   cut: true
 * });
 * // => 'Wonde\nrful\nworld'
 *
 */

function wordWrap(subject) {
  var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
  var subjectString = coerce_to_string.coerceToString(subject);

  var _determineOptions = determineOptions(options),
      width = _determineOptions.width,
      newLine = _determineOptions.newLine,
      indent = _determineOptions.indent,
      cut = _determineOptions.cut;

  if (subjectString === '' || width <= 0) {
    return indent;
  }

  var subjectLength = subjectString.length;
  var substring = subjectString.substring.bind(subjectString);
  var offset = 0;
  var wrappedLine = '';

  while (subjectLength - offset > width) {
    if (subjectString[offset] === ' ') {
      offset++;
      continue;
    }

    var spaceToWrapAt = subjectString.lastIndexOf(' ', width + offset);

    if (spaceToWrapAt >= offset) {
      wrappedLine += indent + substring(offset, spaceToWrapAt) + newLine;
      offset = spaceToWrapAt + 1;
    } else {
      if (cut) {
        wrappedLine += indent + substring(offset, width + offset) + newLine;
        offset += width;
      } else {
        spaceToWrapAt = subjectString.indexOf(' ', width + offset);

        if (spaceToWrapAt >= 0) {
          wrappedLine += indent + substring(offset, spaceToWrapAt) + newLine;
          offset = spaceToWrapAt + 1;
        } else {
          wrappedLine += indent + substring(offset);
          offset = subjectLength;
        }
      }
    }
  }

  if (offset < subjectLength) {
    wrappedLine += indent + substring(offset);
  }

  return wrappedLine;
}
/**
 * Determine the word wrap options. The missing values are filled with defaults.
 *
 * @param  {Object} options  The options object.
 * @return {Object}          The word wrap options, with default settings if necessary.
 * @ignore
 */

function determineOptions(options) {
  return {
    width: coerce_to_number.coerceToNumber(options[OPTION_WIDTH], 75),
    newLine: coerce_to_string.coerceToString(options[OPTION_NEW_LINE], '\n'),
    indent: coerce_to_string.coerceToString(options[OPTION_INDENT], ''),
    cut: coerce_to_boolean.coerceToBoolean(options[OPTION_CUT], false)
  };
}

module.exports = wordWrap;