Multiple transform support

I’ve got a collection of transforms that don’t really make sense to be run individually. I’d like to provide a straightforward way to run them all against a group of files. I don’t see a way to do this with jscodeshift currently, but it seems useful.

ava-codemods does this by running jscodeshift once per transform. It’s a bit brute-force, but it’ll work for now until (if?) jscodeshift adds support.

[stevecooperorg]

A cheap and cheerful approach is to create a ‘master’ transform which uses the output of one transform as the input to the next. This is working fairly well for me; wouldn’t call it production code but for the hacking I’ve been doing it suffices. Might be useful to someone else;

import fix1 from './fix1'
import fix2 from './fix2'
import fix3 from './fix3'

module.exports = function(file, api, options) {
    const fixes = [fix1,fix2,fix3];
    let src = file.source;
    fixes.forEach(fix => {
        if (typeof(src) === "undefined") { return; }
        src = fix({ ...file, source:src }, api, options);
    });
    return src;
};

[fkling]

That seems very reasonable to me. As a first step, we can pass multiple transforms to the workers and have them apply each one in series (will have to check how custom parser selections impacts this, but I think it should work without problem).

Later we could avoid code generation from the AST and provide a way to “chain” transforms and reuse the existing AST. That would require some thought around custom parsers though.