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- var baseToString = require('./_baseToString'),
- castSlice = require('./_castSlice'),
- hasUnicode = require('./_hasUnicode'),
- isObject = require('./isObject'),
- isRegExp = require('./isRegExp'),
- 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 (hasUnicode(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;
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