Question

I know that this is simple terminology, but I can’t get it via google searching… what is it called when the value of a variable being assigned passes through?

An example in php:

<?php 
if($bob = 5){ echo 'The assignment came through as a truthy value!, bob now equals '.$bob.'!'; } 
if($bob = false){ echo 'The assignment occurred again, but the value of the assignment is the value "false", so this if block will not be executed!. Bob now equals '.$bob.'!'; } 
echo ' Finally, bob is a: '.(string) $bob; 
?>

An example in javascript:

bob = bob || {};

Answer 1

In your first example, you’re using assignment as an expression; that is, the assignment statement returns the value assigned (this behavior is a common source of bugs; often people accidentally use = instead of == in their condition).

The second example is using the short-circuiting behavior of the || operator.