Extract all specific properties from a nested array of objects

Question

I have a nested array of objects. I would like to get an object that only provides me the onClick property as the key and the value as null. I am able to navigate to the first level, but I am unable to navigate down further. How do I go forward doing it?

 const headers = [{ id: 'title1', title: 'Title 1', children: [ { title: 'Children 1', child: [ { title: 'Child 1', id: 'child1Id', onClick: 'child1Click', url: '/child1' }, { title: 'Child 2', id: 'child2Id', onClick: 'child2Click' } ] }, { title: 'Children 2', child: [ { title: 'Child 3', id: 'child3Id', onClick: 'child3Click', }, { title: 'Child 4', id: 'child4Id', onClick: 'child4Click' } ] } ] }, { id: 'title2', title: 'Title 2', privilege: '', children: [{ title: 'Children 3', privilege: '', child: [{ title: 'Child 5', id: 'child5Id', onClick: 'child3Click', url: '/child5', privilege: '' }, { title: 'Child 6', id: 'child6Id', onClick: 'child6Click', url: '/child6', privilege: '' } ] }, { title: 'Children 4', privilege: '', child: [{ title: 'Child 7', id: 'child7Id', onClick: 'child7Click', url: '/child7', privilege: '' }, { title: 'Child 8', id: 'child8Id', onClick: 'child8Click', url: '/child8', privilege: '' } ] } ] } ]; const routesMap = ({ onClick, children }) => (onClick? { [onClick]: null }: _.flatMap(children, routesMap)); const routeStates = _.assign({}, ..._.flatMap(headers, routesMap)); console.log(routeStates)

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Expected Output:

  {
      child1Click: null,
      child2Click: null,
      child3Click: null,
      child4Click: null,
      child5Click: null,
      child6Click: null,
      child7Click: null,
      child8Click: null,
  }

Please advice. Any help is highly appreciated.

Answer 1

Using vanilla JS you can use 3 nested map loops to get the onClick values, and return a an object with the value as property. Use Array.flat() to convert to a single array, and spread into Object.assign() to get an object.

 const fn = headers => Object.assign({}, ...headers.map(({ children }) => children.map(({ child }) => child.map(({ onClick }) => ({ [onClick]: null }))) ) // extract onClick values.flat(Infinity) // flatten to a single array ) const headers = [{"id":"title1","title":"Title 1","children":[{"title":"Children 1","child":[{"title":"Child 1","id":"child1Id","onClick":"child1Click","url":"/child1"},{"title":"Child 2","id":"child2Id","onClick":"child2Click"}]},{"title":"Children 2","child":[{"title":"Child 3","id":"child3Id","onClick":"child3Click"},{"title":"Child 4","id":"child4Id","onClick":"child4Click"}]}]},{"id":"title2","title":"Title 2","privilege":"","children":[{"title":"Children 3","privilege":"","child":[{"title":"Child 5","id":"child5Id","onClick":"child3Click","url":"/child5","privilege":""},{"title":"Child 6","id":"child6Id","onClick":"child6Click","url":"/child6","privilege":""}]},{"title":"Children 4","privilege":"","child":[{"title":"Child 7","id":"child7Id","onClick":"child7Click","url":"/child7","privilege":""},{"title":"Child 8","id":"child8Id","onClick":"child8Click","url":"/child8","privilege":""}]}]}] const routeStates = fn(headers) console.log(routeStates)

With lodash you can use _.flatMapDeep() instead of Array.flat() :

 const fn = headers => Object.assign({}, ... _.flatMapDeep(headers, ({ children }) => _.map(children, ({ child }) => _.map(child, ({ onClick }) => ({ [onClick]: null }))) ) // extract onClick values and flatte ) const headers = [{"id":"title1","title":"Title 1","children":[{"title":"Children 1","child":[{"title":"Child 1","id":"child1Id","onClick":"child1Click","url":"/child1"},{"title":"Child 2","id":"child2Id","onClick":"child2Click"}]},{"title":"Children 2","child":[{"title":"Child 3","id":"child3Id","onClick":"child3Click"},{"title":"Child 4","id":"child4Id","onClick":"child4Click"}]}]},{"id":"title2","title":"Title 2","privilege":"","children":[{"title":"Children 3","privilege":"","child":[{"title":"Child 5","id":"child5Id","onClick":"child3Click","url":"/child5","privilege":""},{"title":"Child 6","id":"child6Id","onClick":"child6Click","url":"/child6","privilege":""}]},{"title":"Children 4","privilege":"","child":[{"title":"Child 7","id":"child7Id","onClick":"child7Click","url":"/child7","privilege":""},{"title":"Child 8","id":"child8Id","onClick":"child8Click","url":"/child8","privilege":""}]}]}] const routeStates = fn(headers) console.log(routeStates)

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Answer 2

try to access it in a loop and to access it try this as it is an object...

for ( let i = 0; i < headers.length; i++ ) {

   for (let j = 0; j < headers[i].children.length; j++ ) {

     for (let k = 0; k < headers[i].children[j].child.length; j++ ) {

       console.log( headers[i].children[j].child[k].onClick);

    }

  }

}

it will print as follows...

  child1Click,
  child2Click,
  child3Click,
  child4Click,
  child5Click,
  child6Click,
  child7Click,
  child8Click

if you want to set the all childClick to null try adding this..

console.log( headers[i].children[j].child[k].onClick: null);

i hope it helps

Answer 3

I borrowed a solution I found here to create this:

var headers = [
    //...
];
var newObj = {};

function iterate(obj) {
    Object.keys(obj).forEach(key => {

    if (key === 'onClick') {
        newObj[obj[key]] = 'null';
    }

    if (typeof obj[key] === 'object') {
            iterate(obj[key])
        }
    })
}

iterate(headers);
console.log(newObj);