Check and return nested javascript object via key (array support)

get.js

const get = (obj, target, fallback) => {
  try {
    return eval(`obj${target}`)
  } catch (e) {
    return fallback
  }
}

const obj = {
  a: {
    b: [
      { c: 'wow' },
      { d: 'bam' }
    ],
    e: {
      f: 'zap'
    }
  },
  z: [
    {
      name: 'jane'
    }
  ]
}

const arr = [
  'jane'
]

get(obj, '.z[0].name') // jane
get(obj, '.a') // { b: ..., e: ... }
get(obj, '.a.e.f') // 'zap'
get(null, '.a.e.f') // undefined
get(undefined, '.a.e.f', 'fallback') // 'fallback'
get(obj, '.a.b') // [{ c: 'wow' }, { d: 'bam' }]
get(obj, '.a.b[1].d') // 'bam'
get(obj, '.a.b[3].d') // undefined
get(obj, '.a.b[3].d', undefined) // undefined
get(obj, '.a.b[3].d', null) // null
get(obj, '.a.b[3].d', 'fallback') // 'fallback'
get(obj, '.x') // undefined
get(arr, '[0]') // jane
get(arr, '[1]') // undefined
get(arr, '.y', null) // undefined