[CLI/core] custom compilers

[relu91]

This PR add supports for custom compilers in the Servient runtime. Currently, I tested only ts-node but in principle also others might work. I managed to run this simple script inside node-wot:

/// <reference types="../types/wot" />

WoT.produce({}).then( (thing:WoT.ExposedThing) => {
    console.log(thing.getThingDescription().id)
})

to run it: npm i ts-node && wot-servient --compiler ts-node main.ts

Notice: I used wam typescript project template (i.e. custom type definitions) and I needed to use /// <reference types="../types/wot" /> (see point 2 below).

.However, there still a couple of open points:

1. cli.ts is getting pretty messy. I think It wasn't originally designed to be a simple interface, now it is evolved in a quite complex command-line tool. Probably it needs a refactor.
2. typescript examples still not work. The problem is how ts-node handles types (see here) and how we defined our API type definitions. There still an open issue on the scripting-api repo so I did not go ahead and I'll wait until we make a final decision there.
3. if this PR will be merged, PR fix(cli): allow loading of files transpiled from typescript #240 is obsolete.

[danielpeintner]

@relu91 thank you for your work!

Some thoughts below

• typescript examples still not work. The problem is how ts-node handles types (see here) and how we defined our API type definitions. There still an open issue on the scripting-api repo so I did not go ahead and I'll wait until we make a final decision there.

This is sad :-(

• if this PR will be merged, PR fix(cli): allow loading of files transpiled from typescript #240 is obsolete.

I think the overall issue #171 is just half-solved. I think there are more aspects:

1. allow loading transpiled TS files directly -> solved
2. Unfortunately the _original TS file is not supported (which would be the ultimate/ideal solution)
3. (related to 2.) we still should have an automated approach to transpile TS to JavaScript

Anyway I am OK with merging this improvement.
@sebastiankb @egekorkan do you have any concerns doing so?

[relu91]

This is sad :-(

I know 😢 , I did my best to solve the issue but, finally, I didn't have the time to find a good solution.

• if this PR will be merged, PR fix(cli): allow loading of files transpiled from typescript #240 is obsolete.

I think the overall issue #171 is just half-solved. I think there are more >aspects:

1. allow loading transpiled TS files directly -> solved

2. Unfortunately the _original TS file is not supported (which would be the ultimate/ideal solution)

3. (related to 2.) we still should have an automated approach to transpile TS to JavaScript

allow loading transpiled TS files directly -> solved
Unfortunately the _original TS file is not supported (which would be the ultimate/ideal solution)
(related to 2.) we still should have an automated approach to transpile TS to JavaScript

Right, the issue is still open. I think that fixing the typings might help. If we do not need to import wot-typescript-definitions then we don't have in the output file those lines:

Object.defineProperty(exports, "__esModule", { value: true }); // maybe this will stay
require("wot-typescript-definitions");
let WoT;
let WoTHelpers;

Then in ts-node, we could use typesRoot option which removes the requirement for /// .

Anyway I am OK with merging this improvement.

Thanks, one step at a time and we'll get there 👍