Code Quiz

Awaiting Inside forEach

A subtle async bug where forEach silently ignores awaited promises inside its callback.

Codejavascript

const fs = require('fs').promises;

async function readAll(files) {
  const contents = [];
  files.forEach(async (file) => {
    const data = await fs.readFile(file, 'utf8');
    contents.push(data);
  });
  return contents;
}

readAll(['a.txt', 'b.txt']).then((result) => {
  console.log(result.length); // expects 2, logs 0
});

Why does readAll return an empty array instead of the file contents?

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