A functional approach to lower casing object values

lower-case-object-values-functional.js

import { expect } from 'chai'

const lowerCaseValues = (object, paths) =>
  Object.assign(lowerCaseObjectValues(object), partialObject(object, paths))

const lowerCaseObjectValues = object => {
  return Object.entries(object).reduce((updated, [key, value]) => {
    const isString = typeof value === 'string'
    const isObject = typeof value === 'object'

    if (isObject) {
      updated[key] = lowerCaseObjectValues(value)

      return updated
    }

    updated[key] = isString ? value.toLowerCase() : value

    return updated
  }, {})
}

const partialObject = (object, paths) => {
  if (!paths.length) {
    return object
  }

  const partialObject = {}

  paths.forEach(path => {
    const nodes = path.split('.')
    const pathValue = nodes.reduce((o, i) => o[i], object)

    let partial = partialObject

    while (nodes.length > 1) {
      const node = nodes.shift()

      partial = partial[node] = partial[node] || {}
    }

    partial[nodes[0]] = pathValue
  })

  return partialObject
}

describe('testing', () => {
  it('accepts ignore keys nested keys as using . notation', () => {
    const control = {
      name: 'Daniel',
      foo: {
        bar: 'Wiz',
        deeply: {
          nested: 'Control'
        }
      }
    }
    const expected = {
      name: 'daniel',
      foo: {
        bar: 'Wiz',
        deeply: {
          nested: 'Control'
        }
      }
    }

    expect(lowerCaseValues(control, ['foo.bar', 'foo.deeply.nested'])).to.eql(expected)
  })
})