Convert an object to an array with the object keys chained with dots. So `{ a: 1, b: { c: 2 } }` comes back as `['a', 'b.c']`

flatMap.js

const isNumeric = value => (value == Number(value)) ? 'number' : 'string' // eslint-disable-line

        let keys = []
        let prependable = ''
        const flatMap = obj => {
          Object
            .keys(obj)
            .forEach(key => {
              if (typeof obj[key] !== 'object' && isNumeric(key) !== 'number') {
                keys.push(`${prependable}${key}`)
                return
              }

              if (typeof obj[key] === 'object') {
                prependable += `${key}.`
                flatMap(obj[key])
                prependable = ''
              }
            })

          keys = keys.sort()
        }

        flatMap(YOUR_OBJ)