nodejs文本文件的读写
文本文件的换行符
方法一:
var EOL = fileContents.indexOf("\r\n") >= 0 ? "\r\n" : "\n";
方法二:
var EOL = (process.platform === 'win32' ? '\r\n' : '\n')
删除文件
var fs = require("fs");
console.log("Going to delete an existing file");
fs.unlink('input.txt', function(err) {
if (err) {
return console.error(err);
}
console.log("File deleted successfully!");
});
小文件的异步与同步读写
var fs = require("fs");
console.log("Going to write into existing file");
fs.writeFile('input.txt', 'Simply Easy Learning!', function(err) {
if (err) {
return console.error(err);
}
console.log("Data written successfully!");
console.log("Let's read newly written data");
fs.readFile('input.txt', function (err, data) {
if (err) {
return console.error(err);
}
console.log("Asynchronous read: " + data.toString());
});
});
同步和异步的对比:
var fs = require("fs");
// Asynchronous read
fs.readFile('input.txt', function (err, data) {
if (err) {
return console.error(err);
}
console.log("Asynchronous read: " + data.toString());
});
// Synchronous read
var data = fs.readFileSync('input.txt');
console.log("Synchronous read: " + data.toString());
console.log("Program Ended");
读写大文件
var fs = require("fs");
var data = '';
// Create a readable stream
var readerStream = fs.createReadStream('input.txt');
// Set the encoding to be utf8.
readerStream.setEncoding('UTF8');
// Handle stream events --> data, end, and error
readerStream.on('data', function(chunk) {
data += chunk;
});
readerStream.on('end',function() {
console.log(data);
});
readerStream.on('error', function(err) {
console.log(err.stack);
});
console.log("Program Ended");
输出如下:
Program Ended
Tutorials Point is giving self learning content
to teach the world in simple and easy way!!!!!
使用async/await
const fs = require('fs').promises;
try {
const data = await fs.readFile('file1.js'); // need to be in an async function
console.log(data); // the contents of file1.js
} catch (error) {
console.log(error)
}
const data = "Hello my name is Hugo, I'm using the new fs promises API";
try {
await fs.writeFile('file1.txt', data); // need to be in an async function
} catch (error) {
console.log(error)
}