Angular 2 链式 Promise 并传递拒绝

Question

应该是一个简单的问题，但是我找不到关于如何做到这一点的文档。

像这样链接一个承诺：

// Making a promise, no problem
let promise = new Promise((resolve, reject) => {
    let data = {}; // do something
    reject(data);
});

// First chain, no problem
promise.then(data => {
    console.log('Success callback', data); // This will not be called
}).catch(err => {
    console.log('Error callback', err); // This WILL be called
})

// Second chain, acts as resolved
.then(data => {
    console.log('Level 2 success', data); // This WILL be called
}).catch(err => {
    console.log('Level 2 error', err); // This will NOT be called
});

我了解，除非我传递第一个 catch 回调的拒绝，否则后续的 then 将被视为已解决。

那么...如何从 catch 函数中调用拒绝？

Answer 1

见https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Promise/catch

您需要在 catch 处理程序中抛出异常，例如拒绝第二个链。

// First chain, no problem
promise.then(data => {
    console.log('Success callback', data); // This will not be called
}).catch(err => {
    console.log('Error callback', err); // This will NOT be called
    throw "zonk";
})