How to overwrite values ​​in nested objects?

Question

JavaScript

There is an object:

const data = {
  name1: {
    blblaDate: '12-31-2021',
    arr: [
      {
        blablaDate: '12-31-2021',
      },
    ],
  },
  name2: {
    blblaDate: '12-31-2021',
    arr: [
      {
        blablaDate: '12-31-2021',
      },
    ],
  },
}

It can be nested as much as you like. We need to find all the keys that contain Dateand change the values: ->

blablaDate: '12-31-2021'blablaDate: '31.12.2021'

Answer 1

const replaceValues = (val, test, replacer) =>
  val instanceof Array
    ? val.map(n => replaceValues(n, test, replacer))
    : val instanceof Object
      ? Object.fromEntries(Object
          .entries(val)
          .map(([ k, v ]) => [
            k,
            test(k, v)
              ? replacer(v)
              : replaceValues(v, test, replacer)
          ])
        )
      : val;


const newData = replaceValues(
  data,
  k => k.includes('Date'),
  v => v.replace(/(\d+)-(\d+)-/, '$2.$1.')
);