In the realm of Javascript, the variable `foo` is not simply a

Question

In the realm of Javascript, the variable `foo` is not simply a

I'm feeling a bit perplexed about a situation I came across while working on an application.

Within my object, there exists a method named move which carries out the following actions (in simplified form) when a list item is clicked.

var board = {
  move: function() {
     var unique_id = Puzzle.pieces.id = 28;
     // Further operations involving the unique_id variable.
  },
}

Subsequently, throughout the application, Puzzle.pieces.id is utilized to assign IDs to various elements in this manner:

$('#puzzle-piece-' + Puzzle.pieces.id + '');

After contemplating its purpose for some time, it dawned on me that: When the method is called, unique_id assigns a temporary property to the pieces object within the Puzzle namespace object. Therefore, upon clicking a new list item, the property gets replaced with a new value.

If my interpretation is correct, is it customary to swiftly establish a temporary value accessible across an entire application? If not, what exactly is its intended function?

javascript

Answer 1

Answer №1

Here you will find an explanation:

 var unique_id = Puzzle.pieces.id = 28;

performs the same action as the following:

 var unique_id;
 Puzzle.pieces.id = 28;
 unique_id = Puzzle.pieces.id;

This code snippet assigns the value of 28 to the "id" property of the Puzzle.pieces object, and then it assigns that same value to the local variable unique_id. The key point to remember is that the assignment to the "id" property occurs before the assignment to the local variable, and that the "id" property and the local variable are not directly connected besides sharing the same value. They can be changed independently without affecting each other.

The "id" property does not have a temporary status. If it was already present, its value gets updated; if it wasn't there, it gets created. In both cases, the property will persist until explicitly removed.

edit — As noted in a comment, the Puzzle.pieces object may have a setter function for the "id" property, which could modify the assigned value. Consequently, the true equivalent would be

 var unique_id;
 Puzzle.pieces.id = 28;
 unique_id = 28;

The initialization statement

var unique_id = Puzzle.pieces.id = 28;

is essentially interpreted as

var unique_id = (Puzzle.pieces.id = 28);

and the result of the expression on the right side of the outer = will always be 28.

Answer 2

Here you will find an explanation:

 var unique_id = Puzzle.pieces.id = 28;

performs the same action as the following:

 var unique_id;
 Puzzle.pieces.id = 28;
 unique_id = Puzzle.pieces.id;

This code snippet assigns the value of 28 to the "id" property of the Puzzle.pieces object, and then it assigns that same value to the local variable unique_id. The key point to remember is that the assignment to the "id" property occurs before the assignment to the local variable, and that the "id" property and the local variable are not directly connected besides sharing the same value. They can be changed independently without affecting each other.

The "id" property does not have a temporary status. If it was already present, its value gets updated; if it wasn't there, it gets created. In both cases, the property will persist until explicitly removed.

edit — As noted in a comment, the Puzzle.pieces object may have a setter function for the "id" property, which could modify the assigned value. Consequently, the true equivalent would be

 var unique_id;
 Puzzle.pieces.id = 28;
 unique_id = 28;

The initialization statement

var unique_id = Puzzle.pieces.id = 28;

is essentially interpreted as

var unique_id = (Puzzle.pieces.id = 28);

and the result of the expression on the right side of the outer = will always be 28.

Answer 3

Answer №2

const id = Game.tiles.new_id = 15;

translates to

Assign Game.tiles.new_id as 15. By assigning it, the value returned is 15. Assign id to that returned value.

Answer 4

const id = Game.tiles.new_id = 15;

translates to

Assign Game.tiles.new_id as 15. By assigning it, the value returned is 15. Assign id to that returned value.

Answer 5

Answer №3

let id = Puzzle.pieces.id = 28;

This can be rewritten as:

Puzzle.pieces.id = 28;
let id = Puzzle.pieces.id;

Storing the id in a local variable like id has its advantages. It makes it easier to refer to the id, and it also helps minifiers compress the code further by potentially shortening id to something like a.

As mentioned in the comments, a more accurate equivalent would be:

let id = 28;    
Puzzle.pieces.id = 28;

Answer 6

let id = Puzzle.pieces.id = 28;

This can be rewritten as:

Puzzle.pieces.id = 28;
let id = Puzzle.pieces.id;

Storing the id in a local variable like id has its advantages. It makes it easier to refer to the id, and it also helps minifiers compress the code further by potentially shortening id to something like a.

As mentioned in the comments, a more accurate equivalent would be:

let id = 28;    
Puzzle.pieces.id = 28;

Answer 7

Answer №4

Assigning a value of 28 to unique_id directly may result in it being converted to an integer. However, if pieces.id is not in integer format, then unique_id could potentially take on a different data type.

Answer 8

Assigning a value of 28 to unique_id directly may result in it being converted to an integer. However, if pieces.id is not in integer format, then unique_id could potentially take on a different data type.

In the realm of Javascript, the variable `foo` is not simply a

Answer №1

Answer №2

Answer №3

Answer №4

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