What does using multiple = operators do in Javascript? [duplicate]

Question

For example:

What does

this.head = this.tail = new Node(value)

do? How does javascript interpret this line?

Is this the same as writing:

this.head = new Node(value);
this.tail = new Node(value);

If so, is there any limitation on when and where this one line approach can be used?

a = b = c is equal to a = (b = c), see operator precedence — ASDFGerte
– ASDFGerte, Commented Sep 21, 2021 at 21:05
Does this answer your question? Multiple left-hand assignment with JavaScript — Ervin Szilagyi
– Ervin Szilagyi, Commented Sep 21, 2021 at 21:05

Barmar · Accepted Answer · 2021-09-21 21:06:27Z

0

No, it's assigning the same value to both variables. So it's equivalent to

this.tail = new Node(value);
this.head = this.tail;

Your equivalence would create 2 different Node objects, but there's only 1.

answered Sep 21, 2021 at 21:06

Barmar

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