mirror of
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108 lines
3.1 KiB
JavaScript
108 lines
3.1 KiB
JavaScript
/**
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* lodash (Custom Build) <https://lodash.com/>
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* Build: `lodash modularize exports="npm" -o ./`
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* Copyright jQuery Foundation and other contributors <https://jquery.org/>
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* Released under MIT license <https://lodash.com/license>
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* Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
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* Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
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*/
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var baseIteratee = require('lodash._baseiteratee'),
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rest = require('lodash.rest');
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/** Used as the `TypeError` message for "Functions" methods. */
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var FUNC_ERROR_TEXT = 'Expected a function';
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/**
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* A faster alternative to `Function#apply`, this function invokes `func`
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* with the `this` binding of `thisArg` and the arguments of `args`.
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*
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* @private
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* @param {Function} func The function to invoke.
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* @param {*} thisArg The `this` binding of `func`.
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* @param {Array} args The arguments to invoke `func` with.
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* @returns {*} Returns the result of `func`.
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*/
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function apply(func, thisArg, args) {
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var length = args.length;
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switch (length) {
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case 0: return func.call(thisArg);
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case 1: return func.call(thisArg, args[0]);
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case 2: return func.call(thisArg, args[0], args[1]);
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case 3: return func.call(thisArg, args[0], args[1], args[2]);
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}
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return func.apply(thisArg, args);
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}
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/**
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* A specialized version of `_.map` for arrays without support for iteratee
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* shorthands.
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*
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* @private
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* @param {Array} array The array to iterate over.
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* @param {Function} iteratee The function invoked per iteration.
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* @returns {Array} Returns the new mapped array.
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*/
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function arrayMap(array, iteratee) {
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var index = -1,
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length = array.length,
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result = Array(length);
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while (++index < length) {
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result[index] = iteratee(array[index], index, array);
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}
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return result;
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}
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/**
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* Creates a function that iterates over `pairs` and invokes the corresponding
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* function of the first predicate to return truthy. The predicate-function
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* pairs are invoked with the `this` binding and arguments of the created
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* function.
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*
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* @static
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* @memberOf _
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* @since 4.0.0
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* @category Util
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* @param {Array} pairs The predicate-function pairs.
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* @returns {Function} Returns the new composite function.
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* @example
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*
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* var func = _.cond([
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* [_.matches({ 'a': 1 }), _.constant('matches A')],
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* [_.conforms({ 'b': _.isNumber }), _.constant('matches B')],
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* [_.constant(true), _.constant('no match')]
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* ]);
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*
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* func({ 'a': 1, 'b': 2 });
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* // => 'matches A'
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*
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* func({ 'a': 0, 'b': 1 });
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* // => 'matches B'
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*
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* func({ 'a': '1', 'b': '2' });
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* // => 'no match'
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*/
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function cond(pairs) {
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var length = pairs ? pairs.length : 0,
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toIteratee = baseIteratee;
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pairs = !length ? [] : arrayMap(pairs, function(pair) {
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if (typeof pair[1] != 'function') {
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throw new TypeError(FUNC_ERROR_TEXT);
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}
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return [toIteratee(pair[0]), pair[1]];
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});
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return rest(function(args) {
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var index = -1;
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while (++index < length) {
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var pair = pairs[index];
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if (apply(pair[0], this, args)) {
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return apply(pair[1], this, args);
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}
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}
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});
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}
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module.exports = cond;
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