explodeTree in Javascript

explodeTree.js

// Function for exploding an array of strings representing files on disk into a tree structure.

// Takes something like this
var files = [
    'debug.js',
    'users/create.js',
    'users/edit.js',
    'users/list/a.js',
    'users/list/b.js'];

// and turns it into this
var expectedObj = {
    'debug': 'debug',
        'users': {
        'create': 'create',
            'edit': 'edit',
            'list': {
            'a': 'a',
                'b': 'b'
        }
    }
};

function explodeTree(files, delimiter) {
    function getType(obj) {
        var type = Object.prototype.toString.call(obj);
        if (type.indexOf('Array') !== -1) {
            return 'array';
        } else if (type.indexOf('String') !== -1) {
            return 'string';
        } else if (type.indexOf('Undefined') !== -1) {
            return 'undefined';
        } else {
            return 'unknown';
        }
    }
    
    var obj = {};
    if (!delimiter) {delimiter = '/';}

    files.map(function (file) {
        var file = file.split('.').shift();
        var paths = file.split(delimiter);
        if (paths.length > 1) {
            var key = paths.shift();
        } else {
            var key = paths[0];
        }

        switch (getType(obj[key])) {
            case 'undefined':
                obj[key] = paths.join(delimiter);
                break;
            case 'string':
                obj[key] = [obj[key], paths.join(delimiter)];
                break;
            case 'array':
                obj[key].push(paths.join(delimiter));
                break;
        }
    });

    for (var key in obj) {
        var val = obj[key];
        switch (getType(val)) {
            case 'array':
                obj[key] = explodeTree(val, delimiter);
                break;
        }
    }

    return obj;
};



// Test that the function works, relying on Underscore
var obj = explodeTree(files);
if (!_.isEqual(obj, expectedObj)) {
    console.log('FAIL', obj);
} else {
    console.log('PASS');
}