Object merge

annotated.js

function m( // named function, for recursion / deeper nested objects
 a // first object
,b // second
,c // placeholder
){
 for(c in b) //loop
     b.hasOwnProperty(c) && ( // must be own prop
       (typeof a[c])[0]=='o' ? // if the type is an object.
           m(a[c],b[c]) : // call the merge function on the object
           a[c]=b[c] // or just override it
       )
}

index.js

function m(a,b,c){for(c in b)b.hasOwnProperty(c)&&((typeof a[c])[0]=='o'?m(a[c],b[c]):a[c]=b[c])}

LICENSE.txt

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2011 Arnout Kazemier <blog.3rd-Eden.com>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.

package.json

{
  "name": "merge",
  "description": "merge objects",
  "keywords": [
    "merge",
    "objects",
    "together" 
  ]
}

test.js

function m(a,b,c){for(c in b)b.hasOwnProperty(c)&&((typeof a[c])[0]=='o'?m(a[c],b[c]):a[c]=b[c])}

var FIRST = {
  1:1
, 2:2
, "three":"three"
, "four": [1,2,3,4,5]
, "more":{
    "five": 5
  , "six": "six"
  , "seven": [1,2,3,4,5,6,7]
  }
};

var moar = {
  1:2
, 2:3
, "three":"seven"
, "four": [4,5,7]
, "more":{
    "five": 4
  , "six": "hello world"
  , "seven": "pewpew"
  , "foo":"bar"
  }
};

m(FIRST,moar);
console.log(FIRST);

better compat in same number of bytes:

function m(a,b,c){for(c in b)if(b.hasOwnProperty(c))typeof a[c]=='object'?m(a[c],b[c]):a[c]=b[c]}

you still have a lot of room left. how about adding return a, and the ability to extend n objects? useful for creating a new object non-destructively.

I have been pondering what to do with the last bytes i got left, I was thinking of adding a recursion check so you don't create a infinite loop when one of `b`'s properties reference b again.

…

On May 25, 2011, at 2:56 PM, jed wrote: better compat in same number of bytes: ``` javascript function m(a,b,c){for(c in b)if(b.hasOwnProperty(c))typeof a[c]=='object'?m(a[c],b[c]):a[c]=b[c]} ``` you still have a lot of room left. how about adding `return a`, and the ability to extend n objects? useful for creating a new object non-destructively. ## Reply to this email directly or view it on GitHub: https://gist.github.com/988478

that sounds expensive, but if you can pull it off...

i think returning a value and allowing m({}, objA, objB) would be the way to go, since folks expect that behavior.

The easiest way for recursion checking would be adding each value in the array, and doing a indexOf check on that. But allowing multiple arguments would also be fairly easy to implement.

…

that sounds expensive, but if you can pull it off... i think returning a value and allowing `m({}, objA, objB)` would be the way to go, since folks expect that behavior. ## Reply to this email directly or view it on GitHub: https://gist.github.com/988478