No.

Those two are most relevant to the demo:

• https://blogs.oracle.com/developers/post/fetching-graphql-data-in-mlejavascript
• https://blogs.oracle.com/developers/post/creating-a-graphql-endpoint-within-the-database

But there are many more. Just check-out https://blogs.oracle.com/authors/martin-bach

the benefit of using MLE+GraphQL is the ease of use: the client application was migrated to the database with only very minor changes. Furthermore there is a GraphQL reference implementation available for JavaScript that can be used to build the API. 

There are plenty of examples available. You may want to start with the JavaScript Developer's Guide. There are also plenty of blog posts available at https://blogs.oracle.com/developers/ written by Martin Bach (https://blogs.oracle.com/authors/martin-bach)

Websockets are not supported at the moment

The addition of JavaScript gives more choice to developers, so the answer depends to an extent on the developer’s preference. However, JavaScript does have some natural advantages:

• Access to a large repository of popular modules from npm
• Working with JSON data - functional programming
• Text processing (templating, formatting, …)

JET is a JS library for the client side while MLE is dealing with JS on the Server-Side

MLE comes fully enabled with Oracle Database 23ai and does not need any external components.

MLE JavaScript is another option to create validations, computations, and processes. There are certain operations that cannot be performed with In-Database JavaScript compared to PL/SQL.

Performance is of paramount importance. Oracle is constantly working on improving runtime execution speed for all supported server-side languages. The actual performance of a stored procedure or function depends on the workload. The good news is: the implementation choice isn't binary: you can mix and match code from languages in your application.

Please post your question on the APEX Forum to help you better.

MLE is not deployed as a "component" like JServer, it won't be listed under dba_server_registry. It does not depend on JServer either

MLE/JavaScript is not available with Oracle Database 19c. Oracle Database 21c introduced DBMS_MLE, a package like DBMS_SQL, for executing JavaScript code. Oracle Database 23ai added modules and environments as well as many other features. MLE requires the database to run on Linux x86-64

You can create modules from code stored in files via the CREATE MLE MODULE … USING BFILE syntax. You can then create call specifications on this module and call them. If the function returns JSON, it can be used in pl/sql as usual. However, you cannot “directly” execute JavaScript code stored in a static file.

MLE JavaScript doesn’t provide any immediate advantages for building PWAs in particular over PL/SQL or Java

Yes. Using Execute Server-Side Action and call the JS code.

JavaScript in general (not specifically for APEX) is documented here:
https://docs.oracle.com/en/database/oracle/oracle-database/23/mlejs/index.html. There are help-texts for In-Database JavaScript available for computations, processes, and validations. More help text and documentation will be made available over time

MLE is not available in Oracle 19c. MLE in 23ai fully supports the JSON datatype, so that MLE call specifications can consume JSON arguments, and can also return JSON values that can be used in PL/SQL as usual.

our code editor is using the Monaco library for VS Code for Browser

This is running GraalVM's JavaScript engine, not Node. It's a pure JavaScript engine (EcmaScript 2023) which means there is no window object, NodeJS or Web APIs, except for some Web APIs that we added in the newest release, i.e. Oracle Database 23ai, like fetch. See https://oracle-samples.github.io/mle-modules for more information.

You need APEX 20.2 or later. We recommend to always use the latest. This demo was written using APEX 23.2.6

The demo today showed how to use `fetch`, which is a quite straight-forward (and standardized Web) API to consume web services. See https://blogs.oracle.com/developers/post/fetching-graphql-data-in-mlejavascript  and https://blogs.oracle.com/developers/post/using-the-javascript-fetch-api-in-oracle-database-23c-freedeveloper-release for more info

There are indeed context switches. The cost of which depends on your workload. If you would like to understand the impact you should create a JavaScript port of your most important code and run this as part of a limited PoC internally.

Unfortunately, this isn’t possible

In-Database JavaScript is supported in 21c and 23ai.;MLE modules, environments, and call specifications are only available in 23ai. “Dynamic” execution of JavaScript snippets via dbms_mle.eval() is available in both 21c and 23ai.

JavaScript is only available on x86/Linux at the moment. If there is sufficient customer interest in MLE/JavaScript for Windows a port can be considered.

The MLE team is working with the APEX team to make that happen in the near future