Easy testing with JavaScript

dynamicNestedObject.js

(()=>{
  const test = (result, expect) =>
    `${result === expect && '✅' || '🔴'} ${expect}:${result}` 

  function dynamicNestedObject (total, value) {
    const result = {}
    const keys = 'abcdefghijklmnopqrstuvwxyz'.substring(0, total).split('')
   	const lastIndex = keys.length - 1

    keys.reduce((o, k, i) => {
      const isLastIndex = i === lastIndex
      const val = isLastIndex && value || o[k] || {}
      
      return o[k] = val
    }, result)

    return result
  }

  console.log(dynamicNestedObject(5, 'cool'))

  console.log(test(dynamicNestedObject(3, 'hello').a.b.c, 'hello'))
  console.log(test(dynamicNestedObject(4, 'world').a.b.c.d, 'world'))
})()

https://youtu.be/D6zLI8zrfVs