javascript - Delete object/associative array -

lets have created object , properties in javascript follows-

   var obj = {};    obj['bar'] = 123;    obj['bar']['foo'] = new array();    obj['bar']['xyz'] = new array(); 

after this, push elements 2 arrays. if write

   delete obj['bar']; 

will 2 arrays deleted ?

will 2 arrays deleted ?

they'll eligible garbage collection, assuming nothing else has references them. , nothing will, based on code. when , whether they're actually cleaned up implementation.

but note they're eligible gc before remove bar, because code doing quite odd. see comments:

// creates blank object, far good. var obj = {};  // sets `bar` property number 123. obj['bar'] = 123;  // retrieves value of `bar` (the primitive number 123) , // *converts* `number` instance (object), // creates property on object called `foo`, assigning // blank array it. because number object never stored // anywhere, both , array eligible // garbage collection. value of `obj['foo']` unaffected, // remains primitive number. obj['bar']['foo'] = new array();  // same happens again, temporary number instance , // array created, both eligible // garbage collection; value of `obj['bar']` unaffected. obj['bar']['xyz'] = new array(); 

so didn't have remove bar, arrays instantly eligible garbage collection. happens because in javascript, numbers primitives can automatically promoted number objects — doesn't affect value of property primitive number assigned to. so:

var obj = {}; obj['bar'] = 123; obj['bar']['foo'] = [];         // [] better way write new array() console.log(obj['bar']['foo']); // "undefined" 

if change obj['bar'] = line to:

obj['bar'] = {}; 

or

obj['bar'] = []; // arrays objects 

...then foo , xyz properties not instantly disappear, , arrays stick around until bar cleaned up.