承诺良好实践

Question

快速提问。

对于复杂的 Promise 函数，这样组织代码是否更好：

一个独特的功能，每个功能都尽可能小

var a = () => {
    return new Promise((resolve, reject) => {
        return promise1().then((result1) => {
            return promise2(result1)
        }).then((result2) => {
            return promise3(result2)
        }).then((result3) => {
            return promise4(result3)
        }).then((result4) => {
            resolve(result4)
        }).catch((error) => {
            reject(error)
    })
}

或者像这样

将一些复杂性封装到其他函数中以获得更简单的高级函数。

var b = () => {
    return new Promise((resolve, reject) => {
        return promise12().then((result12) => {
            return promise34(result12)
        }).then((result4) => {
            resolve(result4)
        }).catch((error) => {
            reject(error)
        })
    })
}

var promise12 = () => {
    return new Promise ((resolve, reject) => {
        return promise1().then((result1) => {
            return promise2(result1)
        }).then((result2) => {
            resolve(result2)
        }).catch((error) => {
            reject(error)
        })
    })
}

var promise34 = (result2) => {
    return new Promise ((resolve, reject) => {
        return promise3().then((result3) => {
            return promise4(result4)
        }).then((result) => {
            resolve(result4)
        }).catch((error) => {
            reject(error)
        })
    })
}

Answer 1

没有 "best way" 来组织您的代码。您应该考虑将您的功能分成逻辑模块，以便它们的用法是 "intuitive".

此外，您还没有提到 Max Stoiber 的 generators (functions with * next to them), which is a new javascript ES6 feature. Very likely that in the future these generator function will be a 'de facto' way to handle asynchronous code, because they are well designed to handle it. They are also easy to read and test. You can watch this (currently) free course 来了解更多关于它们的信息。本课程专门设计用于展示如何使用生成器函数编写异步代码。

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