js模拟实现call（很简单的方法）

let objT = { test: '123' };
Function.prototype['myCall'] = function (target, ...args) {
	//this为fncCall
    target.fn = this;
    target.fn(...args);
    delete target.fn;
};

function fncCall(test) {
    console.log(test);
    console.log(this.test);
}
fncCall.myCall(objT, 789);