Is there a way to recurse the following JSON without for-looping the nested children?
My recursive function must be missing a case as it's not returning everything.
iterateTree(node, children) {
console.log(node.name)
if(node.children.length == 0) {
return;
}
for(var i = 0; i < children.length; i++) {
var child_node = children[i];
return this.iterateTree(child_node, child_node.children);
}
}
for(var i = 0; i < sample.length; i++) {
var node = sample[i];
this.iterateTree(node, node.children);
}
var sample = [
{
"name": "hello world",
"children": [
{
"name": "fruits",
"children": []
},
{
"name": "vegetables",
"children": []
},
{
"name": "meats",
"children": [
{
"name": "pork",
"children": []
},
{
"name": "beef",
"children": []
},
{
"name": "chicken",
"children": [
{
"name": "organic",
"children": []
},
{
"name": "farm raised",
"children": []
}
]
},
]
}
]
},
{
"name": "second folder",
"children": []
},
{
"name": "third folder",
"children": [
{
"name": "breads",
"children": []
},
{
"name": "coffee",
"children": [
{
"name": "latte",
"children": []
},
{
"name": "cappucino",
"children": []
},
{
"name": "mocha",
"children": []
},
]
},
]
}
]
Aiming to achieve the following output (similiar to file structure)
hello world
-fruits
-vegetables
-meats
--pork
--beef
--chicken
---organic
---farm raised
second folder
third folder
-breads
-coffee
--latte
--cappucino
--mocha
asked May 9, 2019 at 10:54
fes
2,53511 gold badges40 silver badges59 bronze badges
-
Can you provide a snippet for verification?Krishna Prashatt– Krishna Prashatt2019年05月09日 11:00:25 +00:00Commented May 9, 2019 at 11:00
3 Answers 3
You could create recursive function using reduce method to iterate through your nested data structure, return array and then use join method on that array.
var sample = [{"name":"hello world","children":[{"name":"fruits","children":[]},{"name":"vegetables","children":[]},{"name":"meats","children":[{"name":"pork","children":[]},{"name":"beef","children":[]},{"name":"chicken","children":[{"name":"organic","children":[]},{"name":"farm raised","children":[]}]}]}]},{"name":"second folder","children":[]},{"name":"third folder","children":[{"name":"breads","children":[]},{"name":"coffee","children":[{"name":"latte","children":[]},{"name":"cappucino","children":[]},{"name":"mocha","children":[]}]}]}]
function tree(data, prev = '') {
return data.reduce((r, e) => {
r.push(prev + e.name)
if (e.children.length) r.push(...tree(e.children, prev + '-'));
return r;
}, [])
}
const result = tree(sample).join('\n')
console.log(result)To create same structure in HTML you could use forEach method instead.
var sample = [{"name":"hello world","children":[{"name":"fruits","children":[]},{"name":"vegetables","children":[]},{"name":"meats","children":[{"name":"pork","children":[]},{"name":"beef","children":[]},{"name":"chicken","children":[{"name":"organic","children":[]},{"name":"farm raised","children":[]}]}]}]},{"name":"second folder","children":[]},{"name":"third folder","children":[{"name":"breads","children":[]},{"name":"coffee","children":[{"name":"latte","children":[]},{"name":"cappucino","children":[]},{"name":"mocha","children":[]}]}]}]
function tree(data, parent) {
const ul = document.createElement('ul');
data.forEach(el => {
const li = document.createElement('li');
li.textContent = el.name;
ul.appendChild(li);
if (el.children.length) {
tree(el.children, li)
}
})
parent.appendChild(ul)
}
const parent = document.getElementById('root')
tree(sample, parent)<div id="root"></div>
answered May 9, 2019 at 10:59
Nenad Vracar
122k16 gold badges160 silver badges184 bronze badges
Sign up to request clarification or add additional context in comments.
1 Comment
fes
Thanks this is an impressive function. However what if you wanted to output nested <ul><li></li></ul> combination instead of purely text dash (-).
var sample = [{"name":"hello world","children":[{"name":"fruits","children":[]},{"name":"vegetables","children":[]},{"name":"meats","children":[{"name":"pork","children":[]},{"name":"beef","children":[]},{"name":"chicken","children":[{"name":"organic","children":[]},{"name":"farm raised","children":[]}]}]}]},{"name":"second folder","children":[]},{"name":"third folder","children":[{"name":"breads","children":[]},{"name":"coffee","children":[{"name":"latte","children":[]},{"name":"cappucino","children":[]},{"name":"mocha","children":[]}]}]}]
level = 0;
var hyphens = '';
function recursive_loop(s) {
console.log(hyphens + s.name);
var c = s.children;
if (c.length) hyphens += '-';
var empty = false;
for (let i = 0; i < c.length; i++) {
if (c[i].children) {
recursive_loop(c[i]);
}
if (c[i].children.length)
empty = true;
}
if (empty) hyphens = '';
}
for (let i = 0; i < sample.length; i++) {
recursive_loop(sample[i]);
}Comments
We use object-scan foe many data processing / traversal tasks. It's powerful once you wrap your head around it. Here is how you could solve your question
// const objectScan = require('object-scan');
const display = (input) => objectScan(['**'], {
reverse: false,
rtn: 'entry',
filterFn: ({ value }) => typeof value === 'string'
})(input)
.map(([k, v]) => `${'-'.repeat(k.length / 2 - 1)}${v}`);
const sample = [{ name: 'hello world', children: [{ name: 'fruits', children: [] }, { name: 'vegetables', children: [] }, { name: 'meats', children: [{ name: 'pork', children: [] }, { name: 'beef', children: [] }, { name: 'chicken', children: [{ name: 'organic', children: [] }, { name: 'farm raised', children: [] }] }] }] }, { name: 'second folder', children: [] }, { name: 'third folder', children: [{ name: 'breads', children: [] }, { name: 'coffee', children: [{ name: 'latte', children: [] }, { name: 'cappucino', children: [] }, { name: 'mocha', children: [] }] }] }];
const result = display(sample);
result.forEach((l) => console.log(l));
// => hello world
// => -fruits
// => -vegetables
// => -meats
// => --pork
// => --beef
// => --chicken
// => ---organic
// => ---farm raised
// => second folder
// => third folder
// => -breads
// => -coffee
// => --latte
// => --cappucino
// => --mocha.as-console-wrapper {max-height: 100% !important; top: 0}<script src="https://bundle.run/[email protected]"></script>Disclaimer: I'm the author of object-scan
answered Oct 24, 2020 at 22:31
vincent
2,1893 gold badges19 silver badges30 bronze badges
Comments
lang-js