CODEWITHSUNDEEP
javascriptjquerystringobjectsplit
user977433
user977433

Reputation: 73

Javascript nested objects from string

I've got an empty object and a string:

var obj = {};
var str = "a.b.c";

Is there a way I can turn this into

obj = { a: { b: { c: { } } } }

I can't quite wrap my head around this one and I'm not even sure if it would be possible.

Upvotes: 7

Views: 5530

Answers (5)

vol7ron
vol7ron

Reputation: 42099

var obj = {};
var str = "a.b.c";
var arr = str.split('.');
var tmp = obj;

for (var i=0,n=arr.length; i<n; i++){
   tmp[arr[i]]={};
   tmp = tmp[arr[i]];
}

ES6: 

let str = "a.b.c",
    arr = str.split('.'),
    obj, o = obj = {};

arr.forEach(key=>{o=o[key]={}});

console.log(obj);

ES6/Reduced (array storage unnecessary):

let str = "a.b.c", obj, o = obj = {};

str.split('.').forEach(key=>o=o[key]={});

console.log(obj);

ES6/Array.prototype.reduce:

let str = "a.b.c", last;

let obj = str.split('.').reduce((o, val) => {
  if (typeof last == 'object')
    last = last[val] = {};
  else
    last = o[val] = {};

  return o;
}, {});

console.log(obj);

Upvotes: 10

Narendra Yadala
Narendra Yadala

Reputation: 9664

This recursive function returns you the string representation of the desired object

//Usage: getObjectAsString('a.b.c'.split(/\./))
function getObjectAsString (array){
   return !array.length ? '{}' 
             : '{"' + array[0] + '":' + getObjectAsString (array.slice(1)) + '}';
}

Now you can convert the output of getObjectAsString into object using 

JSON.parse(getObjectAsString('a.b.c'.split(/\./)))

EDIT: Removed 'Input as String' version as it works only for single letter subparts in the namespace such as the one given in the question (a.b.c) which is generally not the case.

Upvotes: 3

Marshall
Marshall

Reputation: 4766

Here's my take on it:

function ensureKeys(str, obj) {
    for(var parts = str.split('.'), i=0, l=parts.length, cache=obj; i<l; i++) {
        if(!cache[parts[i]]) { 
            cache[parts[i]] = {};
        }
        cache = cache[parts[i]];
    }

    return obj;
}

var obj = {};
ensureKeys('a.b.c', obj);
// obj = { a: { b: { c: {} } } }

Upvotes: 0

Joe
Joe

Reputation: 82594

Here you go:

var string = "a.b.c",
   array = string.split('.');
JSON.parse("{\"" + array.join('": {\"') + "\": {" +array.map(function () {return '}'}).join('') + "}")

Example

Upvotes: 0

BNL
BNL

Reputation: 7133

This is from the yui2 yahoo.js file.

YAHOO.namespace = function() {
  var a=arguments, o=null, i, j, d;
  for (i=0; i<a.length; i=i+1) {
      d=(""+a[i]).split(".");
      o=YAHOO;

      // YAHOO is implied, so it is ignored if it is included
      for (j=(d[0] == "YAHOO") ? 1 : 0; j<d.length; j=j+1) {
          o[d[j]]=o[d[j]] || {};
          o=o[d[j]];
      }
  }

  return o;
};

See the source for documentation.

https://github.com/yui/yui2/blob/master/src/yahoo/js/YAHOO.js

Upvotes: 3

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