Set a deeply nested value or get the value of a deeply nested key using dot-separated-string path. E.g: 'some.deeply.nested.key'

nested_value_henlpers.ts

let data: Record<string, any> = { initial: "something" }
let key = "root.field.subField"

const setNestedValue = (obj: Record<string, any>, path: string, value) => {
  return path.split(".")
    .reduce((acc, cur, index, arr) => index === arr.length - 1 ? acc[cur] = value : acc[cur] = {}, obj)

}

const getNestedValue = (obj: Record<string, any>, path: string, defaultValue?: any) =>
  path.split('.').reduce((acc, cur) => (acc ? acc[cur] : defaultValue), obj);



setNestedValue(data, key, "Some Nested Value")
setNestedValue(data, "just", "Some Value")

function flatternKeys(obj: Record<string, any>, prefix?: string, allowNullorUndefined: boolean = false, allowFalsyValue: boolean = true): any {
  return Object.keys(obj).flatMap((key, i, arrr) => {
    let path = prefix ? `${prefix}.${key}` : key
    return !obj[key] ? (obj[key] === 0 || obj[key] === NaN) && allowFalsyValue ? [key] : allowNullorUndefined ? [key] : [] : typeof obj[key] !== "object"
      ? [key]
      : [path, ...flatternKeys(obj[key], path, allowNullorUndefined, false)]
  })
}

let data = {
    ignoreMe: NaN,
    zeroThat: 0,
    initial: "something",
    just: "Some Value",
    root: {
        field: {
            subField: {
                someArr: [],
                notMe: undefined,
                neitherMe: null,
                 ignoreMe: NaN,
    zeroThat: 0,
                last:"Some Nested Value"}
        }
    }
}

console.log("res", flatternKeys(data))


console.log(data)
console.log(getNestedValue(data, key, undefined))