[JS WordWrap] Strip and ellipsize text characters exceeding the max

word-wrap.js

/**
 * This utility function shortens passed text to desired length
 *
 * e.g. wordWrap(str, { maxWidth: 150, moreIndication: '...' })
 *
 * @param {String} str text that requires shortening
 * @param {Object} opt the wrapping options
 *    {Number} maxWidth the max width of the text
 *    {string} moreIndication indicator to append to the end
 */
export default function wordWrap (str, opt = {}) {
  let { maxWidth, moreIndication } = {
    maxWidth = 150,
    moreIndication = '...', 
    ...opt
  }
  
  let newLineStr = '\n'
  let done = false
  let found = false
  let len = str.length
  let res = ''

  do {
    found = false

    // Inserts new line at first whitespace of the line
    for (let i = maxWidth - 1; i >= 0; i--) {
      if (testWhite(str.charAt(i))) {
        res = [str.slice(0, i), newLineStr].join(moreIndication)
        str = str.slice(maxWidth - 1, i + 1)
        found = true
        break
      }
    }
    // Inserts new line at maxWidth position, the word is too long to wrap
    if (!found) {
      res = [str.slice(0, maxWidth), newLineStr].join(moreIndication)
      str = str.slice(maxWidth)
    }

    if (str.length < maxWidth) {
      done = true
    }

  } while (!done)

  return res.trim() === moreIndication ? '' : res.trim()
}

function testWhite (x) {
  let white = new RegExp(/^\s$/)
  return white.test(x.charAt(0))
}