Create string paths from nested object in Javascript

Question

I'm trying to turn a nested object that represents my file system into an array of strings that represent the file paths for each folder and file.

Input:

let obj = {
  'app': {
    'body': {
      'abs': {
        'muscles.txt': 1
      },
      'foot.js': 1,
      'hand.txt': 1,
      'leg.txt': 1
    },
    'cat.txt': 1,
    'dog.js': 1,
    'writing': {
      'pen.txt': 1,
      'phone.txt': 1
    }
  }
};

Output:

  [
  '/app', 
  '/app/body',
  '/app/body/abs/',
  '/app/body/abs/muscles.txt',
  '/app/body/foot.js',
  '/app/body/hand.txt',
  ...
]

What I have so far (it's not working):

function filePaths(obj, oldKey = '', store = []) {
  for (let key in obj) {
    if (typeof obj[key] === 'object') {
      store.push('/' + key);
      filePaths(obj[key], key, store);
    } else {
      store.push('/' + oldKey + '/' + key);
    }
  }
  return store;
}

filePaths(obj);

Your output has paths that sometimes have a trailing slash (/app/body/abs/) and sometimes not (/app, /app/body). Do you want the result with or without that slash, or is there another criteria by which to include it or not? — CRice
– CRice, Commented Aug 2, 2018 at 23:45
Yes, sorry, this is a mistake on my part. I wanted no trailing slash. thank you for your answer. — Philip-lf
– Philip-lf, Commented Aug 3, 2018 at 21:18

Sylwester · Accepted Answer · 2018-08-02 23:51:12Z

3

Here is a working version:

let obj = {
  'app': {
    'body': {
      'abs': {
        'muscles.txt': 1
      },
      'foot.js': 1,
      'hand.txt': 1,
      'leg.txt': 1
    },
    'cat.txt': 1,
    'dog.js': 1,
    'writing': {
      'pen.txt': 1,
      'phone.txt': 1
    }
  }
};

function filePaths(obj, prefix = '', store = []) {
  for (let key in obj) {
    const curPath = `${prefix}/${key}`;
    if (typeof obj[key] === 'object') {
      store.push(curPath);      
      filePaths(obj[key], curPath, store);
    } else {
      store.push(curPath);      
    }
  }
  return store;
}

console.log(filePaths(obj));

So I've kept most of your code, but changed the fact that while you kept the "old" key I keep the current path and it serves as a prefix for all the files and as a prefix for all the directories that will get the current key appended.

answered Aug 2, 2018 at 23:51

Sylwester

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1 Comment

Philip-lf Over a year ago

Thank you Sylwester, I knew I was close, but my logic was slightly off.

CRice · Accepted Answer · 2018-08-02 23:55:07Z

1

Here's a recursive solution that leverages the Object.keys method with the spread operator, concat, and map:

let obj = {
  'app': {
    'body': {
      'abs': {
        'muscles.txt': 1
      },
      'foot.js': 1,
      'hand.txt': 1,
      'leg.txt': 1
    },
    'cat.txt': 1,
    'dog.js': 1,
    'writing': {
      'pen.txt': 1,
      'phone.txt': 1
    }
  }
};

function filePaths(obj, prefix = "", store = []) {
  if (typeof obj !== "object") return [prefix];
  return (prefix && [prefix] || []).concat(...Object.keys(obj).map(k => filePaths(obj[k], prefix + "/" + k, store)))
}

console.log(filePaths(obj))

answered Aug 2, 2018 at 23:55

CRice

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Comments

ggorlen · Accepted Answer · 2020-01-11 22:32:58Z

You're on the right track with recursion. For each call, loop over every property in the current object, make a path for the property and add it to the result array. If the property keys to an object, it's a non-terminal node and is called recursively to add paths for its children.

const pathify = (o, res=[], path=[]) => {
  for (const dir in o) {
    const s = path.join("/");
    res.push(`/${s ? `${s}/${dir}` : dir}`);

    if (typeof o[dir] === "object") {
      pathify(o[dir], res, path.concat(dir));
    }
  }

  return res;
};

const obj = {
  'app': {
    'body': {
      'abs': {
        'muscles.txt': 1
      },
      'foot.js': 1,
      'hand.txt': 1,
      'leg.txt': 1
    },
    'cat.txt': 1,
    'dog.js': 1,
    'writing': {
      'pen.txt': 1,
      'phone.txt': 1
    }
  }
};

console.log(pathify(obj));

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