81 lines
2.7 KiB
JavaScript
81 lines
2.7 KiB
JavaScript
/**
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* Lo-Dash 2.3.0 (Custom Build) <http://lodash.com/>
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* Build: `lodash modularize modern exports="npm" -o ./npm/`
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* Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/>
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* Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE>
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* Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
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* Available under MIT license <http://lodash.com/license>
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*/
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var bind = require('./../lodash.bind'),
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identity = require('./../lodash.identity'),
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setBindData = require('./../lodash._setbinddata'),
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support = require('./../lodash.support');
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/** Used to detected named functions */
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var reFuncName = /^\s*function[ \n\r\t]+\w/;
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/** Used to detect functions containing a `this` reference */
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var reThis = /\bthis\b/;
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/** Native method shortcuts */
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var fnToString = Function.prototype.toString;
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/**
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* The base implementation of `_.createCallback` without support for creating
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* "_.pluck" or "_.where" style callbacks.
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*
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* @private
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* @param {*} [func=identity] The value to convert to a callback.
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* @param {*} [thisArg] The `this` binding of the created callback.
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* @param {number} [argCount] The number of arguments the callback accepts.
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* @returns {Function} Returns a callback function.
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*/
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function baseCreateCallback(func, thisArg, argCount) {
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if (typeof func != 'function') {
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return identity;
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}
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// exit early for no `thisArg` or already bound by `Function#bind`
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if (typeof thisArg == 'undefined' || !('prototype' in func)) {
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return func;
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}
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var bindData = func.__bindData__;
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if (typeof bindData == 'undefined') {
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if (support.funcNames) {
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bindData = !func.name;
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}
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bindData = bindData || !support.funcDecomp;
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if (!bindData) {
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var source = fnToString.call(func);
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if (!support.funcNames) {
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bindData = !reFuncName.test(source);
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}
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if (!bindData) {
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// checks if `func` references the `this` keyword and stores the result
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bindData = reThis.test(source);
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setBindData(func, bindData);
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}
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}
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}
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// exit early if there are no `this` references or `func` is bound
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if (bindData === false || (bindData !== true && bindData[1] & 1)) {
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return func;
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}
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switch (argCount) {
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case 1: return function(value) {
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return func.call(thisArg, value);
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};
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case 2: return function(a, b) {
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return func.call(thisArg, a, b);
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};
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case 3: return function(value, index, collection) {
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return func.call(thisArg, value, index, collection);
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};
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case 4: return function(accumulator, value, index, collection) {
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return func.call(thisArg, accumulator, value, index, collection);
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};
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}
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return bind(func, thisArg);
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}
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module.exports = baseCreateCallback;
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