javascript - “listener” 参数必须是函数类型。 MacOS 上的 Node.JS 9.3.0_1 有问题

Question

这是我从官方文档中获得的代码，并进行了一些修改:

let file = fs.createWriteStream( "data/test.txt" );

let httpOptions = "https://google.com";
const req = https.request( httpOptions, ( response ) => {

    response.on( 'data', ( chunk ) => {

        response.pipe( file );

        file.on( "finish", () => {} )
            .on( "close", () => { file.close(); } )
            .on( "error", ( err ) => { console.log( "!!! Error: " + err ); } );

    } );

});

req.on( 'error', (e) => {
    console.error(e);
});

req.end();

我在这一行得到:““监听器”参数必须是函数类型”:

.on( "close", () => { file.close(); } )

我做错了什么？我添加了“关闭”处理程序，因此它应该可以正常工作，但事实并非如此。

这是完整的错误:

    events.js:180
        throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'listener', 'Function');
        ^

    TypeError [ERR_INVALID_ARG_TYPE]: The "listener" argument must be of type Function
        at _addListener (events.js:180:11)
        at WriteStream.addListener (events.js:240:10)
        at WriteStream.close (fs.js:2298:10)
        at WriteStream.file.on (/Users/.../myscript.js:229:32) <=== This is .on( "close", () => { file.close(); } )
        at WriteStream.emit (events.js:159:13)
        at fs.close (fs.js:2141:14)
        at FSReqWrap.oncomplete (fs.js:149:20)

Node.js: 9.3.0_1, MacOS X: 10.12.5

UPD: If I change these lines to new ones:

file.on( "finish", () => { } )
.on( "close", () => { } )

没有任何错误，但输出文件为空。所以 node.js 不允许我正确关闭文件:)

Answer 1

我无法复制错误。如果我从你的问题中获取代码，添加两个 require 调用，然后运行它，我不会收到错误(在 *nix 上，不是 Mac OS，但它们非常相似)。但我也没有在文件中获取数据。

在 data 事件中调用 pipe 没有多大意义。相反:

const fs = require("fs");
const https = require("https");

let file = fs.createWriteStream( "data/test.txt" );
// *** Note moving the code setting up these handlers out of the `data` callback
// That said, since you're using `pipe`, I don't think you need the close handler,
// and your finish handler doesn't do anything
file.on( "finish", () => {} )
    .on( "close", () => { file.close(); } )
    .on( "error", ( err ) => { console.log( "!!! Error: " + err ); } );

let httpOptions = "https://google.com";
const req = https.request( httpOptions, ( response ) => {
    // *** Do the pipe
    response.pipe( file );
});

req.on( 'error', (e) => {
    console.error(e);
});

req.end();

如果我这样做，我会在文件中获取数据(特别是 302 的文本)。 (我也明白了，没有错误，没有向 file 添加任何处理程序。)