小编MrF*_*ion的帖子

我在追逐.then()一个承诺的链接时遇到了麻烦.执行以下代码时:

var prom = new Promise(function(resolve, reject) {
  //let's always fail
  reject(Error("buuuu!"));
});

var thenable = 
prom.then(
    function(done) {
        console.log("First handler: Done!: Argument: ", done);
        return "First then: DONE";
    },
    function(fail) {
        console.error("First handler: Fail!. Argument: ", fail);
        return "First then: FAIL";
    }
).then(
    function(done) {
        console.info("Second handler: Done!.  Argument: ", done);
    },
    function(fail) {
        console.error("Second handler: Fail!.  Argument: ", fail);
    }
);

这将在控制台中打印以下内容:

First handler: Fail!. Argument:  Error {stack: (...), message: "buuuu!"}
Second handler: Done!.  Argument:  First …