Deep-copying in JavaScript

Re:Deep-copying in JavaScript by amarshall on Thursday January 25, 2018 @02:37PM (#16233849)

The object is still passed by value, however the object itself contains references, which may be mutated. If objects were pass by reference then you’d end up with {a: 2} at the end:

    let a = {a: 1}
    
    function foo(a) {
      a = {a: 2}
    }
    
    foo(a)
    a //=> {a: 1}

Don’t confuse passing a mutable entity by value with pass by reference.

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Re:Deep-copying in JavaScript by mnarayan01 on Thursday January 25, 2018 @03:58PM (#16234605)

> The object is still passed by value, however the object itself contains references, which may be mutated.

This would imply that:

  var v = 1;

  (function (o) {
    o.a = 2;
  }({ a: v });

  console.log(v);  // => 2

The whole "objects are pass-reference-by-value" is obviously annoying and confusing, but we're kind of stuck with it.

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Re:Deep-copying in JavaScript by shkkmo on Thursday January 25, 2018 @04:16PM (#16234742)

Apparently there is another term (which I hadn't heard) which is: call-by-sharing

https://en.m.wikipedia.org/wiki/Evaluation_strategy#Call_by_...

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