I’m trying to aggregate data to create the array with objects where keys are going to be directories and inside of them will be files. I would like to achieve that kind of structure:

  const output = [
    {
      directory1: [
        {
          ...filecontent,
        },
        {
          ...filecontent,
        },
      ],
    },
    {
      directory2: [
        {
          ...filecontent,
        },
        {
          ...filecontent,
        },
      ],
    },
  ];

I try to do it with reduce, I get proper directory but somehow cannot process data to get desired output

 const output = files.reduce((acc: any[], file) => {
      const directory = getDirectory(file.uri);
      if (Object.keys(acc).includes(directory)) {
        acc[directory].push(file)
      } else {
        acc.push({ [directory]: file });
      }
      return acc;
    }, []);

>Solution :

There might be a better way to do that that involves only iterating over the file array once.

But a simpler solution that is easier to read and maintain is to aggregate your data like this:

const output = {
  directory1: [
    {
      ...filecontent,
    },
    {
      ...filecontent,
    },
  ],
  directory2: [
    {
      ...filecontent,
    },
    {
      ...filecontent,
    },
  ]
}

You can accomplish this by doing this:

const initialOutput = files.reduce((acc, file) => {
  const directory = getDirectory(file.uri)
  if (!output[directory]) {
    acc[directory] = [file]
  } else {
    acc[directory].push(file)
  }
  return acc
}, {})

Then afterwards convert it to the format that you want like this:

const formattedOutput = [];

for (const key in initialOutput) {
  if (initialOutput.hasOwnProperty(key)) {
    const newObject = {};
    newObject[key] = initialOutput[key];
    formattedOutput.push(newObject);
  }
}

This iterates over your files and then your aggregated output which might be less performant if that matters a lot to you, but it works.