javascript - JS如何用单行设置范围之外的值

Question

这个问题已经有答案了:

Object destructuring without var, let or const (4 个回答)

Is it possible to destructure onto an existing object? (Javascript ES6) (17 个回答)

已关闭 3 年前。

如果函数 calculateAvgGainLoss回复包括 avgGain, avgLoss我们可以这样得到这些值。

const { avgGain, avgLoss } = calculateAvgGainLoss(prices);

我想将这些值设置为在函数外部定义的变量。我怎样才能做到这一点 ？下面的例子。

describe("test", () => {
  let avgGain: number, avgLoss: number;
  it("Calculate average gain & loss", () => {
    const prices = [...];
    /*...This isn't working, has to be changed...*/ { avgGain, avgLoss } = calculateAvgGainLoss(prices);
    expect(avgGain).toBe(0.24);
    expect(avgLoss).toBe(0.1);
  });

});

Answer 1

以 { 开头会混淆解析器(它是作用域的开头吗？对象？等等)。只需用括号将行括起来即可绕过此问题:

describe("test", () => {
  let avgGain: number, avgLoss: number;
  it("Calculate average gain & loss", () => {
    const prices = [...];
    ({ avgGain, avgLoss } = calculateAvgGainLoss(prices)); // <--
    expect(avgGain).toBe(0.24);
    expect(avgLoss).toBe(0.1);
  });

});