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var baseToString = require('./_baseToString'),
castSlice = require('./_castSlice'),
isObject = require('./isObject'),
isRegExp = require('./isRegExp'),
reHasComplexSymbol = require('./_reHasComplexSymbol'),
stringSize = require('./_stringSize'),
stringToArray = require('./_stringToArray'),
toInteger = require('./toInteger'),
toString = require('./toString');
/** Used as default options for `_.truncate`. */
var DEFAULT_TRUNC_LENGTH = 30,
DEFAULT_TRUNC_OMISSION = '...';
/** Used to match `RegExp` flags from their coerced string values. */
var 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 "...".
*
* @static
* @memberOf _
* @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.
* @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) {
var length = DEFAULT_TRUNC_LENGTH,
omission = DEFAULT_TRUNC_OMISSION;
if (isObject(options)) {
var separator = 'separator' in options ? options.separator : separator;
length = 'length' in options ? toInteger(options.length) : length;
omission = 'omission' in options ? baseToString(options.omission) : omission;
}
string = toString(string);
var strLength = string.length;
if (reHasComplexSymbol.test(string)) {
var strSymbols = stringToArray(string);
strLength = strSymbols.length;
}
if (length >= strLength) {
return string;
}
var end = length - stringSize(omission);
if (end < 1) {
return omission;
}
var 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)) {
var match,
substring = result;
if (!separator.global) {
separator = RegExp(separator.source, toString(reFlags.exec(separator)) + 'g');
}
separator.lastIndex = 0;
while ((match = separator.exec(substring))) {
var newEnd = match.index;
}
result = result.slice(0, newEnd === undefined ? end : newEnd);
}
} else if (string.indexOf(baseToString(separator), end) != end) {
var index = result.lastIndexOf(separator);
if (index > -1) {
result = result.slice(0, index);
}
}
return result + omission;
}
module.exports = truncate;