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preface

In server-side code using Node.js, if you are using the Express framework, there are usually two ways to respond to a request:

1 / / method
app.get("/end".(req, res, next) = >{
    res.end(xxx);
});
2 / / method
app.get("/send".(req, res, next) = >{
    res.send(xxx);
});
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So what’s the difference between these two approaches? What are the application scenarios? That’s what I need to make clear today.

Express the res. End ()

define

It can quickly end a response without requiring any data.

This method actually comes from the Node core, specifically the response.end() method of http.serverResponse.use:

grammar

res.end([data[, encoding]][, callback])
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Parameter analysis:

  • data <string> | <Buffer>
  • encoding <string>
  • callback <Function>

in-depth

If an object is passed to the res.end() method, an error occurs:

Express the res of the send ()

define

Send an HTTP response message to the requesting client.

grammar

res.send([body[,statusCode]])
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The body argument can be Buffer, Object, String, Boolean, or Array.

in-depth

Express res.send() also calls http.serverResponse.use response.end() :

// node_modules/express/lib/response.js
res.send = function send(body) {
  var chunk = body;
  varencoding; ...if (req.method === 'HEAD') {
    // skip body for HEAD
    this.end();
  } else {
    // respond
    this.end(chunk, encoding);
  }
  return this;
};
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contrast

The same

The res.end() and res.send() methods of Express are similar:

  1. Both end up going back tohttp.ServerResponse.Use 的 response.end()Methods.
  2. Both end the current response process.

The difference between

The res.end() and res.send() methods of Express differ:

  1. The former can only send string or Buffer, while the latter can send any type of data.
  2. Semantically, the former is more suitable for scenarios where there is no response data at all, while the latter is more suitable for scenarios where there is response data.

conclusion

When using the Res.end () and res.send() methods of Express, it is generally recommended to use res.send(). This way, you do not need to care about the format of the response data because the data is processed internally in Express.

~

Thanks for reading!

~

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