Substitution variables in SQLcl Javascript

Erik van Roon

Hope somebody can give me some insight in what I'm doing wrong.....

I'm playing around with some javascript scripts for SQLcl (disclaimer: I know little javascript).

According to (the comments in the script in) this post by Kris Rice:

https://krisrice.io/2016-11-30-sqlcl-custom-input-prompt-and/

the substitution variables that are defined in SQLcl can be accessed through a collection of type "map".

Awesome!

Now, according to this

https://javascript.info/map-set

a map has a number of methods and properties.

Of that list the get(), set() and size() work like a dream.

But has() and delete() tell me "null is not a function", see screenshot.

Why is this? What am I doing wrong or what am I misunderstanding?

Especially has() is one that I would really like to use.

Example with size() which works and has() which doesn't:

script

 // Function writes text and an end-of-line to screen

 function writeLine (line) {

  ctx.write (line + "\n");

 }

 ctx.setSubstitutionOn(true);

 writeLine ("Number of defined substitution variables: " + ctx.getMap().size());

  

 if (ctx.getMap().has("MY_VAR")) {

  writeLine ("Variable exists");

 } else {

  writeLine ("Variable does NOT exist");

 }

/