如何在单行中从单独的变形属性中变形？

Question

const { navigation, currentScreen, childIndex } = this.state
const screen = navigation[currentScreen]

我该如何用一行而不是两行写？

Answer 1

使用{ [currentScreen]: screen }，请确保您事先提取了currentScreen：

const state = { navigation: { foo: 'val' }, currentScreen: 'foo' };

const { navigation, currentScreen, childIndex, navigation: { [currentScreen]: screen } } = state
console.log(screen);

也就是说，真的很难读。我强烈建议您使用当前版本。仅当您处于actually code-golfing时才对高尔夫球场进行编码，否则最好在几乎所有情况下都针对可读性进行优化。

带有navigation而不是对象的数组的示例：

const state = { navigation: ['val1', 'val2', 'val3'], currentScreen: 1 };

const { navigation, currentScreen, childIndex, navigation: { [currentScreen]: screen } } = state
console.log(screen);