How to expand nested array?

Question

JavaScript

There is an object that stores data in which there are nested child arrays. I want all nested child arrays to lie at the same level in the new array.

Any ideas how to do this - only recursive deployment comes to mind?

Answer 1

Only recursively.

const nested = {
  id: 1,
  children: [
    { id: 2 },
    { id: 3,
      children: [{ id: 5 }, { id: 6 }]
    },
    { id: 4 }
  ]
}

const flatten = function(obj) {
  const array = Array.isArray(obj) ? obj : [obj];
  return array.reduce(function(acc, value) {
    acc.push(value);
    if (value.children) {
      acc = acc.concat(flatten(value.children));
      delete value.children;
    }
    return acc;
  }, []);
}

flatten(nested); // => [ { id: 1 }, { id: 2 }, { id: 3 }, { id: 5 }, { id: 6 }, { id: 4 } ]

Answer 2

If I understand correctly, you need to make a flat array.
look at the implementation of flatten and flattenDeep in lodash
or here ready: MDN

Answer 3

I don't know how efficient it is, but it will expand any nesting
for an array of strings or numbers, which will become strings in the final array

arr.toString().split(',')
arr.join().split(',')