Recursive Looping A Object Tree

I have tree object: const tree = [ { key: 'parent1', id: '001', children:[{ key: 'B', id: '002', children: [{key: 'C', id: '003', children: [{key: 'D'

Solution 1:

You could use a function which takes the actual level and returns the callback for the array method.

Inside, the callback displays the key and call the function again with an increased level for next iteration.

functioniter(level) {
    returnfunction (node)  {
        console.log('node', level, node.key);
        (node.children || []).forEach(iter(level + 1));
    };
}

var tree = [{ key: "parent1", id: "001", children: [{ key: "B", id: "002", children: [{ key: "C", id: "003", children: [{ key: "D", id: "004", children: [] }] }] }] }, { key: "parent2", id: "002", children: [{ key: "B", id: "002", children: [{ key: "C", id: "003", children: [{ key: "D", id: "004", children: [] }] }] }] }];

tree.forEach(iter(0));

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Solution 2:

What about:

constprocess = (level = 0) => (parentNode) => {
  console.log(`${level} parentNode: ${parentNode.key}`);
  if (parentNode.children && level < 2) {
    parentNode.children.forEach(process(level + 1));
  }
}

tree.forEach(process());

Solution 3:

Yes, you can trace it easily with recursive function.

For example like this:

const tree = [
    {
        key: "parent1", 
        id: "001", 
        children:[{ key: "B", id: "002", children: [{key: "C", id: "003", children: [{key: "D", id: "004", children: [] }]}], }] 
    },
    {
        key: "parent2", 
        id: "002", 
        children:[{ key: "B", id: "002", children: [{key: "C", id: "003", children: [{key: "D", id: "004", children: [] }]}], }] 
    },
]

functiongoThrough(node, parent = null) {
  if (!node) {
    return;
  }
  node.map((parentNode) => {
    console.log(`node: ${parentNode.key}, parent: ${parent}`);
    goThrough(parentNode.children, parentNode.key);    
  });
}

goThrough(tree);

Solution 4:

function printKey(obj){
    obj.map(x=>{
    console.log(x.key);
    if (x.hasOwnProperty('children')){
    printChild(x.children);
    }
  });
}

Solution 5:

You can iterate over the array recursively like this:

const tree = [
        {
            key: "parent1", 
            id: "001", 
            children:[{ key: "B", id: "002", children: [{key: "C", id: "003", children: [{key: "D", id: "004", children: [] }]}] }] 
        },
        {
            key: "parent2", 
            id: "002", 
            children:[{ key: "B", id: "002", children: [{key: "C", id: "003", children: [{key: "D", id: "004", children: [] }]}] }] 
        }
    ]

functioniterator(tree) {
  tree.forEach((parentNode) => {
    console.log(`Node: ${parentNode.key}`);
    if (parentNode.hasOwnProperty('children')) iterator(parentNode.children)       
  });
}

iterator(tree)