Node.js與其它語言一樣,提供了對文本文件按照行來讀的功能。不過與Ruby,Python等語言不同,Node.js的File System對象并不提供迭代訪問功能。
比如在Ruby中可以這么寫
file = File.new("log1.log")
file.each do |line|
puts line if line =~ /blablabla/
end
在Python中,這個文件迭代可以這么寫(為了Python3,我給print加了括號):
f = open('log1.log','r')
for eachLine in f:
print (eachLine)
f.close()
經姚軍勇同學review,認為上面的python版本寫得不好,下面是改進版:
with open("log1.log", "r") as file:
[print(x) for x in file.readlines()]
但是在Node.js中,要借用一個獨立模塊readline來實現這個功能:
"use strict"
const readline = require('readline')
const fs = require("fs");
const r1 = readline.createInterface({
input: fs.createReadStream("log1.log")
});
var i = 1;
r1.on('line', (line) => {
console.log('Line from file:' + i + ":" + line);
i += 1;
});