Source: \truncate.js
import baseToString from './.internal/baseToString.js'
import castSlice from './.internal/castSlice.js'
import hasUnicode from './.internal/hasUnicode.js'
import isObject from './isObject.js'
import isRegExp from './isRegExp.js'
import stringSize from './.internal/stringSize.js'
import stringToArray from './.internal/stringToArray.js'
/** Used as default options for `truncate`. */
const DEFAULT_TRUNC_LENGTH = 30
const DEFAULT_TRUNC_OMISSION = '...'
/** Used to match `RegExp` flags from their coerced string values. */
const reFlags = /\w*$/
/**
* Truncates `string` if it's longer than the given maximum string length.
* The last characters of the truncated string are replaced with the omission
* string which defaults to "...".
*
* @since 4.0.0
* @category String
* @param {string} [string=''] The string to truncate.
* @param {Object} [options={}] The options object.
* @param {number} [options.length=30] The maximum string length.
* @param {string} [options.omission='...'] The string to indicate text is omitted.
* @param {RegExp|string} [options.separator] The separator pattern to truncate to.
* @returns {string} Returns the truncated string.
* @see replace
* @example
*
* truncate('hi-diddly-ho there, neighborino')
* // => 'hi-diddly-ho there, neighbo...'
*
* truncate('hi-diddly-ho there, neighborino', {
* 'length': 24,
* 'separator': ' '
* })
* // => 'hi-diddly-ho there,...'
*
* truncate('hi-diddly-ho there, neighborino', {
* 'length': 24,
* 'separator': /,? +/
* })
* // => 'hi-diddly-ho there...'
*
* truncate('hi-diddly-ho there, neighborino', {
* 'omission': ' [...]'
* })
* // => 'hi-diddly-ho there, neig [...]'
*/
function truncate(string, options) {
let separator
let length = DEFAULT_TRUNC_LENGTH
let omission = DEFAULT_TRUNC_OMISSION
if (isObject(options)) {
separator = 'separator' in options ? options.separator : separator
length = 'length' in options ? options.length : length
omission = 'omission' in options ? baseToString(options.omission) : omission
}
let strSymbols
let strLength = string.length
if (hasUnicode(string)) {
strSymbols = stringToArray(string)
strLength = strSymbols.length
}
if (length >= strLength) {
return string
}
let end = length - stringSize(omission)
if (end < 1) {
return omission
}
let result = strSymbols
? castSlice(strSymbols, 0, end).join('')
: string.slice(0, end)
if (separator === undefined) {
return result + omission
}
if (strSymbols) {
end += (result.length - end)
}
if (isRegExp(separator)) {
if (string.slice(end).search(separator)) {
let match
let newEnd
const substring = result
if (!separator.global) {
separator = RegExp(separator.source, `${ reFlags.exec(separator) || '' }g`)
}
separator.lastIndex = 0
while ((match = separator.exec(substring))) {
newEnd = match.index
}
result = result.slice(0, newEnd === undefined ? end : newEnd)
}
} else if (string.indexOf(baseToString(separator), end) != end) {
const index = result.lastIndexOf(separator)
if (index > -1) {
result = result.slice(0, index)
}
}
return result + omission
}
export default truncate