以每秒1行的速率解析CSV

I've been trying to find libraries (to avoid re-inventing the wheel) to read a single line on a CSV file and pushing the value to a downstream process.

我一直试图找到库（以避免重新发明*）读取CSV文件中的单行并将值推送到下游进程。

However, I need the read and processing to only happen once per second. Is there a way to do this on Node?

但是，我需要每秒只进行一次读取和处理。有没有办法在Node上执行此操作？

1 个解决方案

#1

I came across a similar problem recently, as I needed a way to read the file one line at a time and not move to the next until I was done processing the previous one.

我最近遇到了类似的问题，因为我需要一种方法一次读取一行文件而不是移动到下一行，直到我完成处理前一行。

I solved it by using promises, stream.pause(), and stream.resume(). You could do it like this:

我通过使用promises，stream.pause（）和stream.resume（）来解决它。你可以这样做：

const Promise = require('bluebird');                        
const fs = require('fs');                                   
const byline = require('byline');                           

function readCSV(file, callback) {
  let stream = fs.createReadStream(file);
  stream = byline.createStream(stream);
  stream.on('data', (line) => {
    stream.pause();
    Promise.resolve(line.toString())
      .then(callback)
      .then(() => setTimeout(() => stream.resume(), 1000));
  });
}

readCSV('file.csv', console.log);

#1