Simple deep cloning function. Works fine with primitive objects/arrays, doesn't work properly with class instances and objects with custom prototypes.

simple-clone-deep.js

const isObject = value => typeof value === "object"

const cloneDeep = (value) => {
  if (!value || !isObject(value)) return value

  if (Array.isArray(value)) return value.map(item => cloneDeep(item))

  return Object.keys(value).reduce((accum, propName) => {
    const propValue = value[propName]
    
    if (Array.isArray(propValue)) {
      return { ...accum, [propName]: propValue.map(item => cloneDeep(item)) }
    }

    if (!isObject(propValue)) return { ...accum, [propName]: propValue }

    return { ...accum, [propName]: cloneDeep(propValue) }
  }, {})
}