Javascript-如何读取文件

Question

I am using readline rd.on('line', function(line) {..... to read in a file line by line. I want to then just consume the file one line at a time starting from the first line and proceeding to the end of the file.

It seems "unshift" on an Array (in order to create a Queue to retain the order) can only take a literal and not a variable.

The main and apparently simplest solution I see for this is to read the file and process int into a string and split(\\n) into an array.

Is there a "better" way? This seems to consume a huge amount of memory and has limits as a result.

Answer 1

There is no reason to push your lines after reading them into an array only to read them again. When handling the line event emitted from the readline module simply process the line then.

Here is the excerpt from the Readline module docs on how to read a file line-by-line:

A common case for readline's input option is to pass a filesystem readable stream to it. This is how one could craft line-by-line parsing of a file:

 const readline = require('readline'); const fs = require('fs'); const rl = readline.createInterface({ input: fs.createReadStream('sample.txt') }); rl.on('line', (line) => { console.log('Line from file:', line); });