sugar/string/internal/truncateString.js

A Javascript utility library for working with native objects.

'use strict';

var isUndefined = require('../../common/internal/isUndefined'),
    mathAliases = require('../../common/var/mathAliases'),
    truncateOnWord = require('./truncateOnWord');

var ceil = mathAliases.ceil,
    floor = mathAliases.floor;

function truncateString(str, length, from, ellipsis, split) {
  var str1, str2, len1, len2;
  if (str.length <= length) {
    return str.toString();
  }
  ellipsis = isUndefined(ellipsis) ? '...' : ellipsis;
  switch(from) {
    case 'left':
      str2 = split ? truncateOnWord(str, length, true) : str.slice(str.length - length);
      return ellipsis + str2;
    case 'middle':
      len1 = ceil(length / 2);
      len2 = floor(length / 2);
      str1 = split ? truncateOnWord(str, len1) : str.slice(0, len1);
      str2 = split ? truncateOnWord(str, len2, true) : str.slice(str.length - len2);
      return str1 + ellipsis + str2;
    default:
      str1 = split ? truncateOnWord(str, length) : str.slice(0, length);
      return str1 + ellipsis;
  }
}

module.exports = truncateString;