Here is an example of the code I'm working with:
ngOnInit{
let p1 : Person = {};
console.log(p1); //Object { }
this.setNull<Person>(p1);
console.log(p1); //Object { }
}
private setNull<T>(obj : T){
obj = null;
}
My objective is to assign a value of null to p1 after calling setNull().
I believe I have effectively explained my issue. Thank you in advance.
My objective is to nullify p1 after utilizing setNull().
It's not possible, as it's not passed by reference but rather an object reference passed by value. Pass by reference does not exist in TypeScript or JavaScript.
In this particular scenario, the most straightforward approach would be to directly assign null to p1. However, for a more complex situation where setNull may not always result in null being assigned to p1, you could use the return value from setNull to update p1:
p1 = someFunction(p1);
Alternatively, consider making p1 a property of a mutable object and passing that object into the function so that p1 can be set to null when necessary.
If setting p1 to null unconditionally without any other logic is your sole purpose, then simply assign null to p1 directly without involving a function.
Everything is being displayed correctly. It is important to note that in JavaScript, Objects are passed by reference. The variable p1 holds a reference which points to an empty object {} in memory.
When you pass this reference to a method, the variable obj also starts pointing to the same empty object {}. Both variables act as pointers at this stage. If you set obj to null, it means that obj now points to null. However, p1 still points to the empty object {}.
To demonstrate that it is indeed pass by reference,
you can try the following code:
var p1 = { "name" : "demo" }
function passByRef (obj) {
obj.name = "demo updated";
}
//call fun with p1
passByRef(p1);
// print p1.name -> it will be the updated one
console.log(p.name);
Therefore, JavaScript behaves similarly to Java where function arguments are passed by reference.
To define an Interface and optionally make the element p1 null, you can follow this syntax:
export Interface IPerson {
bla bla bla
p1? : number; // (array, string or any other type)
}
By ending the property name with a question mark (?), the property is allowed to be null.
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