Extract value from array recursively in javascript

Question

I want to extract the files in this structure recursively. I have done it for the first level, but can't proceed further.

var DirectoryTree = {
    dir: 'project1',
    files: [
        'proj.config', {
            dir: 'src',
            files: [
                'name.htm',
                'dept.htm',
                'salary.htm', {
                    dir: 'scripts',
                    files: [
                        'name.js',
                        'dept.js',
                        'salary.js'
                    ]
                }
            ]
        }, {
            dir: 'project2',
            files: [
                'proj.config', {
                    dir: 'src',
                    files: [
                        'name.htm',
                        'dept.htm',
                        'salary.htm', {
                            dir: 'scripts',
                            files: [
                                'name.js',
                                'dept.js',
                                'salary.js'
                            ]
                        }
                    ]
                }
            ]
        }
    ]
};

Below is the code I have till now. I am kind of stuck here. Can you help me to get the data from the next levels.

function listFiles(dirTree, subFolder){
    var fList=[];
    if(dirTree.files){
        for (var i=0;i<dirTree.files.length;i++){
            if(typeof dirTree.files[i] === 'string'){
                fList.push(dirTree.files[i]);
            }
        }
    }
    if(dirTree.dir){
        return(listFiles(dirTree.dir, subFolder));
    }
    return fList;
}

1.) Are you trying to get all the files? 2.) Why are you trying to do this? — Casey Falk
– Casey Falk, Commented Jul 25, 2014 at 17:21
Also, you are trying to extract values from an object -- not an Array. Be precise. :) — Casey Falk
– Casey Falk, Commented Jul 25, 2014 at 17:22
"2.) Why are you trying to do this?" Smells like homework to me. — Casey Falk
– Casey Falk, Commented Jul 25, 2014 at 17:22
Also, your DirectoryTree doesn't have valid syntax according to JSFiddle. :P — Casey Falk
– Casey Falk, Commented Jul 25, 2014 at 17:25

thefourtheye · Accepted Answer · 2014-07-25 17:36:26Z

You can do this recursively, like this

function getFiles(currentObject, result) {
    var type = Object.prototype.toString.call(currentObject),
        idx;
    if (type === "[object Object]") {
        for (idx in currentObject) {
            if (currentObject.hasOwnProperty(idx) && idx === "files") {
                currentObject[idx].forEach(function(object) {
                    getFiles(object, result);
                });
            }
        }
    } else if (type === "[object Array]") {
        currentObject.forEach(function(object) {
            getFiles(object, result);
        });
    } else if (type === "[object String]") {
        result.push(currentObject);
    }
    return result;
}

console.log(getFiles(DirectoryTree, []))

Output

[ 'proj.config',
  'name.htm',
  'dept.htm',
  'salary.htm',
  'name.js',
  'dept.js',
  'salary.js',
  'proj.config',
  'name.htm',
  'dept.htm',
  'salary.htm',
  'name.js',
  'dept.js',
  'salary.js' ]

Trace · Accepted Answer · 2014-07-25 17:36:52Z

0

I answered a similar question today and solved it using a few underscore functions.
The format of your example is pretty weird, but I would advise again to use a recursive function for this type of reads:

function recursiveFuntion(collection){
    collection.forEach(function(model) { 
        //console.log(model.files); --> Or do whatever you need 
        if(model.files.length > 0){ 
            recursiveFunction(model); 
        }; 
     }); 
}; 

recursiveFuntion(DirectoryTree.files);

The benefit of the recursive function is that it is dynamic.
As you are not working with an array but with an object, you'll need to customise this code.
But this is the basic principle.

answered Jul 25, 2014 at 17:36

Trace

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