手写 call 函数

Function.prototype.call2 = function(context) {
  context = context || global || window;
  context.fn = this;
  const args = [...arguments].slice(1);
  const result = context.fn(...args);
  delete context.fn;
  return result;
};

var a = {};
var b = {
  print: function(content) {
    console.log(content);
  }
};

b.print.call(a, 12);
b.print.call2(a, 12);