Add support ttypescript transformer interface

[cevek]

I wrote a tool which patch ts on the fly and add support for custom transformers from tsconfig.json
https://github.com/cevek/ttypescript

{
    "compilerOptions": {
        "plugins": [
            {
                "customTransformers": {
                    "before": ["ts-transformer-keys"],
                }
            }
        ]
    }
}

but it works slightly different by calling your transformer directly and provide the program as second argument
This is transformer example:

import * as ts from 'typescript';
export default (ctx: ts.TransformationContext, program: ts.Program): ts.Transformer<ts.SourceFile> => {
    return sourceFile => {
        function visitor(node: ts.Node): ts.Node {
            return ts.visitEachChild(node, visitor, ctx);
        }
        return ts.visitEachChild(sourceFile, visitor, ctx);
    };
};

If you accept PR, I can add support for this

[kimamula]

I really love your tool.
However, I feel a little hesitant to expose an additional interface especially for your tool as one can easily wrap my transformer as follows to use it with your tool.

const keysTransformer = require('ts-transformer-keys/transformer').default;
export default (ctx, program) => keysTransformer(program)(ctx);

What do you think?

I hope tsconfig could be written in JS or TS as suggested.

[cevek]

I think about a setting type of transformer, something like that
{module: 'ts-transformer-keys', type: 'program'} that will do it automatically,
because your transformer pattern is common

[kimamula]

Looks like you recently added PluginConfig.type config to support variety of types of transformer functions.

Is it possible to add another PluginConfig.type to support (program: ts.Program) => (ctx: ts.TransformationContext) => TransformerPlugin type of transformer?

[cevek]

So, your pattern already supports - it is program type and it is by default

(program: ts.Program, config?: PluginConfig) => ts.TransformerFactory<ts.SourceFile>
type TransformerFactory = (context: TransformationContext) => Transformer<T>;

so you can just use it like

compilerOptions: {
 plugins: [
   { "transform": "transformer-module",  someConfig: true }
 ]
}

[kimamula]

Ah, I see. That's great, thanks!

Then I close this issue.