40 lines
1.2 KiB
JavaScript
40 lines
1.2 KiB
JavaScript
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var identity = require('../utility/identity');
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/**
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* A specialized version of `baseCallback` which only supports `this` binding
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* and specifying the number of arguments to provide to `func`.
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*
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* @private
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* @param {Function} func The function to bind.
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* @param {*} thisArg The `this` binding of `func`.
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* @param {number} [argCount] The number of arguments to provide to `func`.
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* @returns {Function} Returns the callback.
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*/
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function bindCallback(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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if (thisArg === undefined) {
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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 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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case 5: return function(value, other, key, object, source) {
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return func.call(thisArg, value, other, key, object, source);
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};
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}
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return function() {
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return func.apply(thisArg, arguments);
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};
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}
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module.exports = bindCallback;
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