node_modules/loupe/lib/string.js

import { truncate } from './helpers'

const stringEscapeChars = new RegExp(
  "['\\u0000-\\u001f\\u007f-\\u009f\\u00ad\\u0600-\\u0604\\u070f\\u17b4\\u17b5" +
    '\\u200c-\\u200f\\u2028-\\u202f\\u2060-\\u206f\\ufeff\\ufff0-\\uffff]',
  'g'
)

const escapeCharacters = {
  '\b': '\\b',
  '\t': '\\t',
  '\n': '\\n',
  '\f': '\\f',
  '\r': '\\r',
  "'": "\\'",
  '\\': '\\\\',
}
const hex = 16
const unicodeLength = 4
function escape(char) {
  return escapeCharacters[char] || `\\u${`0000${char.charCodeAt(0).toString(hex)}`.slice(-unicodeLength)}`
}

export default function inspectString(string, options) {
  if (stringEscapeChars.test(string)) {
    string = string.replace(stringEscapeChars, escape)
  }
  return options.stylize(`'${truncate(string, options.truncate - 2)}'`, 'string')
}