how to loop line from `readline.createInterface` method?-CodePudding

I have blow code to read a text file line by line but it complains about an error on the for loop. Type 'Interface' must have a '[Symbol.asyncIterator]()' method that returns an async iterator.ts(2504)

It seems relating to the rl interface created from readline.createInterface.

const fileStream = fs.createReadStream('test.text');

  const rl = readline.createInterface({
    input: fileStream,
    crlfDelay: Infinity,
  });

  for await (const line of rl) {
   ...

CodePudding user response：

The simplest way to read the stream is to use rl.on('line', callback)

function onLine(line) {
  console.log(line);
}

rl.on('line', onLine);

https://stackblitz.com/edit/node-her3vv?file=index.js

for await should work provided it is inside of an async function and your node version is greater than 11.14: https://nodejs.org/api/readline.html#rlsymbolasynciterator

async function readLines() {
  for await (const line of rl) {
    console.log(line);
  }
}

readLines();

https://stackblitz.com/edit/node-rquour?file=index.js