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var identity = require('../utility/identity');
/**
* A specialized version of `baseCallback` which only supports `this` binding
* and specifying the number of arguments to provide to `func`.
*
* @private
* @param {Function} func The function to bind.
* @param {*} thisArg The `this` binding of `func`.
* @param {number} [argCount] The number of arguments to provide to `func`.
* @returns {Function} Returns the callback.
*/
function bindCallback(func, thisArg, argCount) {
if (typeof func != 'function') {
return identity;
}
if (thisArg === undefined) {
return func;
}
switch (argCount) {
case 1: return function(value) {
return func.call(thisArg, value);
};
case 3: return function(value, index, collection) {
return func.call(thisArg, value, index, collection);
};
case 4: return function(accumulator, value, index, collection) {
return func.call(thisArg, accumulator, value, index, collection);
};
case 5: return function(value, other, key, object, source) {
return func.call(thisArg, value, other, key, object, source);
};
}
return function() {
return func.apply(thisArg, arguments);
};
}
module.exports = bindCallback;
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