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var ERROR_MESSAGE = 'Function.prototype.bind called on incompatible ';
var slice = Array.prototype.slice;
var toStr = Object.prototype.toString;
var funcType = '[object Function]';
module.exports = function bind(that) {
var target = this;
if (typeof target !== 'function' || toStr.call(target) !== funcType) {
throw new TypeError(ERROR_MESSAGE + target);
}
var args = slice.call(arguments, 1);
var bound;
var binder = function () {
if (this instanceof bound) {
var result = target.apply(
this,
args.concat(slice.call(arguments))
);
if (Object(result) === result) {
return result;
}
return this;
} else {
return target.apply(
that,
args.concat(slice.call(arguments))
);
}
};
var boundLength = Math.max(0, target.length - args.length);
var boundArgs = [];
for (var i = 0; i < boundLength; i++) {
boundArgs.push('$' + i);
}
bound = Function('binder', 'return function (' + boundArgs.join(',') + '){ return binder.apply(this,arguments); }')(binder);
if (target.prototype) {
var Empty = function Empty() {};
Empty.prototype = target.prototype;
bound.prototype = new Empty();
Empty.prototype = null;
}
return bound;
};
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