Expression Evaluation Short-Circuit

[Chiwinks]

Hello, all!

I'm interested in learning how I might detect syntax errors within various expressions passed into Jint 3.0. Specifically, I'm encountering cases where syntax errors related to undefined variables aren't being flagged due to short-circuiting behavior.

As an example, passing in the following expression evaluates to 'false': false && my_bad_variable

Short-circuiting detects the first false and determines that further evaluation is not necessary.

While this is a valid and expected behavior, it would be helpful under certain conditions to detect the undefined variable and receive an exception like: my_bad_variable is not defined

I would be grateful for any direction you can provide.

[lahma]

Because evaluating the second operand would be against the spec (and generally anything expected) this would be quite hard to achieve.

You could parse the script with esprima and then visit the nodes trying to find invalid identifiers if you know they are invalid.

[Chiwinks]

Thank you, @lahma. I appreciate the quick response and confirming my suspicions around solution complexity. I will try the esprima route. If I find success, I'll post back here.