call apply 模拟实现

function demo(a, b) {
  console.log(a);
  console.log(b);
  console.log(this.value);
}

Function.prototype.call1 = function(context) {
  context = context || {};
  let self = this;
  let args = [];
  for (let i = 1; i < arguments.length; i++) {
    args.push(eval("arguments[" + i + "]"));
  }
  context.fn = self;
  context.fn(...args);
  delete context.fn;
};

Function.prototype.Apply1 = function(context) {
  context = context || {};
  let self = this;
  context.fn = self;
  context.fn(...arguments[1]);
  delete context.fn;
};

demo.call1(
  {
    value: "call1"
  },
  "a",
  "b"
);
demo.Apply1(
  {
    value: "apply1"
  },
  ["c", "d"]
);