es before freezing self
      for (const name of propNames) {
        const value = object[name];
    
        if ((value && typeof value === "object") || typeof value === "function") {
          deepFreeze(value);
        }
      }
    
      return Object.freeze(object);
    }
    
    const obj2 = {
      internal: {
        a: null,
      },
    };
    
    deepFreeze(obj2);
    
    obj2.internal.a = "anotherValue"; // fails silently in non-strict mode
    obj2.internal.a; // null
    

##  Specifications

Specification  
---  
[ ECMAScript Language Specification  
#  sec-object.freeze  ](https://tc39.es/ecma262/multipage/fundamental-
objects.html#sec-object.freeze)  
  
##  Browser compatibility

BCD tables only load in the browser  with JavaScript enabled. Enable
JavaScript to view data.

##  See also

  * [ ` Object.isFrozen() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isFrozen)
  * [ ` Object.preventExtensions() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/preventExtensions)
  * [ ` Object.isExtensible() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isExtensible)
  * [ ` Object.seal() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/seal)
  * [ ` Object.isSealed() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isSealed)

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