nodejs character encoding conversion

During development, we often encounter situations where we need to convert character encodings. For example, the data obtained from the outside is UTF-8 encoded, but our program needs to process GBK encoded data. In order to solve this problem, Node.js provides multiple ways to convert character encodings.

1. Use Buffer object for encoding conversion

Buffer is an object used to process binary data in Node.js, and can also be used for encoding conversion. It provides encoding methods such as utf8, utf16le, latin1, base64, and hex. We can use the Buffer.from() method to convert the data into a buffer object, and then use the toString method of the buffer object to perform encoding conversion.

The following is an example of converting a GBK-encoded string into a UTF-8-encoded string:

const gbkStr = "中文字符串";
const buffer = Buffer.from(gbkStr, "gbk");
const utf8Str = buffer.toString("utf8");
console.log(utf8Str); //输出: 中文字符串

In this example, we first use the Buffer.from() method to The gbkStr string is converted into a buffer object, and the parameter "gbk" specifies the encoding method of conversion. Next, we use the toString() method of the buffer object to convert the buffer object into a utf8-encoded string, thereby achieving the purpose of character encoding conversion.

2. Use iconv-lite library

iconv-lite is a very easy-to-use Node.js module. It provides a variety of encoding conversion functions and supports more than 30 encoding methods. We can install it using npm.

The following is an example to convert a utf8-encoded string into a GBK-encoded string:

const iconv = require("iconv-lite");
const str = "中文字符串";
const buffer = Buffer.from(str, "utf8");
const gbkStr = iconv.decode(buffer, "gbk");
console.log(gbkStr); //输出: 中文字符串

In this example, we first use the Buffer.from() method to convert the utf8Str character The string is converted into a buffer object, and then the iconv.decode() method is used to convert the buffer object into a GBK-encoded string, thereby achieving the purpose of character encoding conversion.

iconv-lite also provides many other encoding conversion methods. For specific usage methods, please refer to the official documentation.

3. Use stream stream for encoding conversion

Node.js provides the stream module for streaming data processing. We can also use stream stream for character encoding conversion. Data is transferred by using a readable stream and a writable stream, and encoding conversions are performed within the streams.

The following is an example of converting a utf8-encoded file into a GBK-encoded file:

const fs = require("fs");
const iconv = require("iconv-lite");

// 创建可读流
const readStream = fs.createReadStream("./utf8.txt");
// 创建可写流
const writeStream = fs.createWriteStream("./gbk.txt");
// 创建一个转换流
const transformStream = iconv.decodeStream("gbk");

readStream
  .pipe(transformStream)
  .pipe(writeStream)
  .on("finish", function () {
    console.log("转换完成");
  });

In this example, we use the fs module to create a readable stream and a writable stream stream, and creates an iconv.decodeStream() conversion stream. Read the data in the readable stream and convert it into gbk encoding, and finally write the converted data to the writable stream through pipe.

Summary

There are many ways to choose from for character encoding conversion in Node.js. We can use Buffer objects, iconv-lite library or stream stream for encoding conversion. These methods can effectively solve the character encoding problems we encounter during the development process. I believe that through the introduction of this article, everyone can better understand the use of these methods, and can flexibly use them in actual development.

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