相关疑难解决方法(0)

我对ES2015中的spread语法和rest参数感到困惑.任何人都能用适当的例子来解释它们之间的区别吗？

我在一些示例代码中遇到了这个,我完全迷失了.

const addCounter = (list) => {
    return [...list, 0];  // This is the bit I am lost on, and I don't know about [...list, 0]
}

显然以上等于以下内容:

const addCounter = (list) => {
    return list.concat([0]);
}

任何建议或解释都非常感谢.

下面，我有2种方法来构造对象数组。

方法1：

const employees = [
  {
    company: 'ABC',
    country: 'IN',
    zip: 123,
    employeeId: 123,
    employeeName: 'p'
  },
  {
    company: 'ABC',
    country: 'IN',
    zip: 123,
    employeeId: 456,
    employeeName: 'q'
  },
  {
    company: 'ABC',
    country: 'IN',
    zip: 123,
    employeeId: 789,
    employeeName: 'r'
  }
];

方法2（使用传播算子）：

const commonParams = {
  company: 'ABC',
  country: 'IN',
  zip: 123
};

const employees = [
  {
    ...commonParams,
    employeeId: 123,
    employeeName: 'p'
  },
  {
    ...commonParams,
    employeeId: 456,
    employeeName: 'q'
  },
  {
    ...commonParams,
    employeeId: 789,
    employeeName: 'r'
  } …