Object basics: Clearer wording/example with mutations & references #29846

wolfdaemon · 2025-07-07T03:40:56Z

This changes the "Reassigning object data type variables" with revised language and an extended example to explain the concept much more initially clear.

Because

This changes the "Reassigning object data type variables" with revised language and an extended example to explain the concept much more initially clear.

This PR

Changes the admonition titled "Reassigning object data type variables" to "Modifying the properties of an object vs. reassigning the object variables"
Changes the verbiage/example of the section to make things more clear, specifically:
- Making a clear difference as to what a "mutation" vs changing the value of a primitive does
  - How the above affects variables that reference vs primitives that have a value on its own
  - Making a clear separating the between the variable name that references the object itself, vs the name/label/reference attached to it.

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This changes the "Reassigning object data type variables" with revised language and an extended example to explain the concept much more initially clear.

mao-sz

Many thanks, I think the idea behind this definitely makes a clearer distinction between mutation and reassignment. Just a couple of wording changes needed which are detailed below.

Could you also address the two linting errors regarding blank lines? And resolve the merge conflict too?

mao-sz · 2025-09-07T21:25:48Z

foundations/javascript_basics/object_basics.md

-#### Reassigning object data type variables
-
-While mutating the object we have a reference to affects all other variables that reference it, reassigning a variable does not change what the other variables refer to. For example:
+#### Mutating the properties of an object vs. reassigning the object variables


I think the new heading is a little verbose for a heading

Suggested change

#### Mutating the properties of an object vs. reassigning the object variables

#### Mutation vs. reassignment

mao-sz · 2025-09-07T21:27:47Z

foundations/javascript_basics/object_basics.md


-// reassigning animal variable with a completely new object
-animal = { species: "cat" };
+// Mutating the properties of the object that both 'animal' and 'dog' reference


The object is being mutated, not the property (which is actually being reassigned)

Suggested change

// Mutating the properties of the object that both 'animal' and 'dog' reference

// Mutating the object that both 'animal' and 'dog' reference

mao-sz · 2025-09-07T21:30:16Z

foundations/javascript_basics/object_basics.md

+console.log(animal); // { species: "bird" }
+console.log(dog); // { species: "cat" }
 ```
+In the first part, when we modify the species property of the object that both `animal` and `dog` reference, the change is reflected in both variables. In the second part, when we reassign the `animal` variable to a new object, the `dog` variable still references the original object, while `animal` now points to the new object.


Fixing with the same as the previous review comment, and a small re-wording to accommodate that.

Suggested change

In the first part, when we modify the species property of the object that both `animal` and `dog` reference, the change is reflected in both variables. In the second part, when we reassign the `animal` variable to a new object, the `dog` variable still references the original object, while `animal` now points to the new object.

In the first part, there is only one object which is referenced by both `animal` and `dog`. When we mutate that object, the change is reflected in both variables. In the second part, when we reassign the `animal` variable to a new object; the `dog` variable still references the original object, while `animal` now points to the new object.

mao-sz · 2025-09-07T21:35:06Z

foundations/javascript_basics/object_basics.md

-
-While mutating the object we have a reference to affects all other variables that reference it, reassigning a variable does not change what the other variables refer to. For example:
+#### Mutating the properties of an object vs. reassigning the object variables
+When you have multiple variables that reference the same object, mutating the properties of that object will affect all the variables that reference it. However, reassigning the object variable to a new object will only change the value of that specific variable, and will not affect the other variables that previously referenced the original object. For example:


Just some small wording tweak given the rest of the review comments. Strength added to the mutate and reassign keywords.

Suggested change

When you have multiple variables that reference the same object, mutating the properties of that object will affect all the variables that reference it. However, reassigning the object variable to a new object will only change the value of that specific variable, and will not affect the other variables that previously referenced the original object. For example:

When multiple variables reference the same object, **mutating** that object will affect all the variables that reference it. However, **reassigning** a variable to a new object will only change the value of that specific variable, and will not automatically reassign any other variable that referenced the original object. For example:

Object basics: Clearer wording/example with mutations & references

ee36ce4

This changes the "Reassigning object data type variables" with revised language and an extended example to explain the concept much more initially clear.

github-actions bot added the Content: Foundations Involves the Foundations content label Jul 7, 2025

rlmoser99 requested review from a team and bycdiaz and removed request for a team July 8, 2025 01:39

mao-sz self-requested a review September 4, 2025 10:53

mao-sz requested changes Sep 7, 2025

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Object basics: Clearer wording/example with mutations & references #29846

Object basics: Clearer wording/example with mutations & references #29846

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wolfdaemon commented Jul 7, 2025

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	#### Mutating the properties of an object vs. reassigning the object variables
	#### Mutation vs. reassignment

	// Mutating the properties of the object that both 'animal' and 'dog' reference
	// Mutating the object that both 'animal' and 'dog' reference

	In the first part, when we modify the species property of the object that both `animal` and `dog` reference, the change is reflected in both variables. In the second part, when we reassign the `animal` variable to a new object, the `dog` variable still references the original object, while `animal` now points to the new object.
	In the first part, there is only one object which is referenced by both `animal` and `dog`. When we mutate that object, the change is reflected in both variables. In the second part, when we reassign the `animal` variable to a new object; the `dog` variable still references the original object, while `animal` now points to the new object.

	When you have multiple variables that reference the same object, mutating the properties of that object will affect all the variables that reference it. However, reassigning the object variable to a new object will only change the value of that specific variable, and will not affect the other variables that previously referenced the original object. For example:
	When multiple variables reference the same object, mutating that object will affect all the variables that reference it. However, reassigning a variable to a new object will only change the value of that specific variable, and will not automatically reassign any other variable that referenced the original object. For example:

Object basics: Clearer wording/example with mutations & references #29846

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wolfdaemon commented Jul 7, 2025

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