Are there pointers in javascript?

I used C++ before and I realized that pointers were very helpful. Is there anything in javascript that acts like a pointer? Does javascript have pointers? I like to use pointers when I want to use something like:

var a = 1;
var b = "a";
document.getElementById(/* value pointed by b */).innerHTML="Pointers";

I know that this is an extremely simple example and I could just use a, but there are several more complex examples where I would find pointers very useful. Any ideas?

Answers:

Answer

No, JS doesn't have pointers.

Objects are passed around by passing a copy of a reference. The programmer cannot access any C-like "value" representing the address of an object.

Within a function, one may change the contents of a passed object via that reference, but you cannot modify the reference that the caller had because your reference is only a copy:

var foo = {'bar': 1};

function tryToMungeReference(obj) {
    obj = {'bar': 2};  // won't change caller's object
}

function mungeContents(obj) {
    obj.bar = 2;       // changes _contents_ of caller's object
}

tryToMungeReference(foo);
foo.bar === 1;   // true - foo still references original object

mungeContents(foo);
foo.bar === 2;  // true - object referenced by foo has been modified
Answer

You bet there are pointers in JavaScript; objects are pointers.

//this will make object1 point to the memory location that object2 is pointing at
object1 = object2;

//this will make object2 point to the memory location that object1 is pointing at 
function myfunc(object2){}
myfunc(object1);

If a memory location is no longer pointed at, the data there will be lost.

Unlike in C, you can't see the actual address of the pointer nor the actual value of the pointer, you can only dereference it (get the value at the address it points to.)

Answer

due to the nature of JS that passes objects by value (if referenced object is changed completely) or by reference (if field of the referenced object is changed) it is not possible to completely replace a referenced object.

However, let's use what is available: replacing single fields of referenced objects. By doing that, the following function allows to achieve what you are asking for:

function replaceReferencedObj(refObj, newObj) {
    let keysR = Object.keys(refObj);
    let keysN = Object.keys(newObj);
    for (let i = 0; i < keysR.length; i++) {
        delete refObj[keysR[i]];
    }
    for (let i = 0; i < keysN.length; i++) {
        refObj[keysN[i]] = newObj[keysN[i]];
    }
}

For the example given by user3015682 you would use this function as following:

replaceReferencedObj(foo, {'bar': 2})
Answer

Technically JS doesn't have pointers, but I discovered a way to imitate their behavior ;)

var car = {
    make: 'Tesla',
    nav: {
       lat: undefined,
       lng: undefined
    }
};

var coords: {
    center: {
       get lat() { return car.nav.lat; }, // pointer LOL
       get lng() { return car.nav.lng; }  // pointer LOL
    }   
};

car.nav.lat = 555;
car.nav.lng = 777;

console.log('*** coords: ', coords.center.lat); // 555
console.log('*** coords: ', coords.center.lng); // 777
Answer

Try this:

//MaybePointer Lib
function MaybePointer(v){
    this.val = v;
}
MaybePointer.prototype.valueOf = function(){ return this.val };

//Your code
var a = new MaybePointer(1);
var b = a;
document.getElementById(b+'').innerHTML="Pointers 1";

var c = new MaybePointer(2);
var b = c;
document.getElementById(b+'').innerHTML="Pointers 2";
<div id="1"></div>
<div id="2"></div>

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