Flatten nested object’s keys into an array, with JS

Question

I have an object, and I’d like to get each "branch" of the "tree" as an array. (Feel free to correct my terminology also!) What I have is like the following:

var features = {
 "f": {
 "t": "100",
 "f": {
 "i": ['150'],
 "b": ['300'],
 "f": {
 "k": 100
 }
 },
 "l": ['255']
 },
 "c": {
 "s": {
 "t": ["100"]
 },
 "t": "100"
 }
};

And I’d like to parse it into the following result, so I can iterate over it again and pass it into another function.

var result = [
 "ffi",
 "fffk",
 "fl",
 "ct"
]

What I have so far is on JS Bin here. Any help or pointers in the right direction would be greatly appreciated! Thanks!

• Etheryte: possible duplicate of Flatten object to array?
• kennethormandy: @Nit I don’t think so, I am just looking for the keys, in a way that retains the entire branch. I appreciate the link, though, it might still be helpful for getting to the end result.

Answer 1

You can try my un-flatten-tree npm module to convert the tree into the list of branches. Also note that 'map' from lodash is used for object traversal.

function walk(tree) {
 return _.map(tree, function (v, k) {
 return {
 name: k,
 items: (typeof v !== 'object' || v instanceof Array) ? [] : walk(v)
 };
 });
}
function getChildNodes(node) {
 return node.items.map(function (item) {
 return {
 name: node.name + item.name,
 items: item.items
 };
 });
}
var result = uft.flatten(walk(features), getChildNodes)
 .filter(function (node) { return node.items.length === 0; })
 .map(function (node) { return node.name; });

Live example:

https://jsfiddle.net/iyegoroff/ut3bz6oc/