babeljs - What's the difference and/or preferred way of updating a deep property? -


this babel/es7 question (for redux reducer use)

i want update "dan" in properties. what's preferred way immutability mind?

it seems try 1 , try 3 merge/update correctly.

is there difference between two? me try 3 wins because it's shortest (if no difference between try 1)

thanks 

const people = { byid: {     gaston : { name:'gaston', age: 22 },      dan : { name: 'gaston', age: 44 }   }  }  const currentid = "dan"  /// // try 1   const thisid = {} thisid[currentid] = {...people.byid[currentid],   age: 20,   sex: 'male', }  const newpeople = {...people,    byid: {...people.byid,     ...thisid   } }  console.log( newpeople  ) // ok  // // try 2  const newpeople2 = {}  newpeople2.byid = {} newpeople2.byid[currentid] = {} newpeople2.byid[currentid]["age"] = 20 newpeople2.byid[currentid]["sex"] = "male"  const newpeople3 = {...people, ...newpeople2}  console.log( newpeople3 )  // nope (not merge)  // // try 3  const newpeople4 = {...people} newpeople4.byid = newpeople4.byid || {}  newpeople4.byid[currentid] = newpeople4.byid[currentid] || {}  newpeople4.byid[currentid]["age"] = 20 newpeople4.byid[currentid]["sex"] = "male"  console.log(newpeople4) // ok

here outputs

try 1   {"byid":{"gaston":{"name":"gaston","age":22},"dan":{"name":"gaston","age":20,"sex":"male"}}}  try 2  {"byid":{"dan":{"age":20,"sex":"male"}}}  try 3  {"byid":{"gaston":{"name":"gaston","age":22},"dan":{"name":"gaston","age":20,"sex":"male"}}}

using spread operator, can do:

const updatedpeople = {   byid: {     ...people.byid,     dan: {       ...people.byid.dan,       age: 20,       sex: "male"     }   } };

if need id dynamic, using computed property keys (an other es6 feature, part of destructuring):

const id = 'dan';  const updatedpeople = {   byid: {     ...people.byid,     [id]: {       ...people.byid[id],       age: 20,       sex: "male"     }   } };

those solutions immutability full proof, though, if you're not familiar es6 syntax, can hard read , if have more complex data, might consider using immutablejs (or kind of immutable library)


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