Expose the tsconfigRaw option in the build API

[iamakulov]

Hey,

Would it be possible to expose the tsconfigRaw option (from the transform API) in the build API as well?

Rationale: We’re using tsconfig.json to provide aliases and overrides for import paths. Eg, one of tsconfig.jsons that ESBuild uses looks like this:

{
    "extends": "../tsconfig.json",
    "compilerOptions": {
        "paths": {
            // Mocks
            "linaria": ["../esbuild/mocks/linaria/index.ts"],
            // Externals
            "react": ["../esbuild/externals/react/index.js"],
            "react-dom": ["../esbuild/externals/react-dom/index.js"],
            "react-dom/unstable-native-dependencies": [
                "../esbuild/externals/react-dom/unstable-native-dependencies/index.js"
            ],
            "react-dom/server": ["../esbuild/externals/react-dom/server/index.js"],
            // Aliases
            "library/*": ["../../../library/src/*"],
            "test/features": ["../test/features.ts"],
            // (10 more lines)
        }
    }
}

The challenge is that we have multiple tsconfigs with slightly different (but mostly common) paths:

Example

// tsconfig.dev.json includes the `linaria` mock + externals + aliases
{
    "extends": "../tsconfig.json",
    "compilerOptions": {
        "paths": {
            // Mocks
            "linaria": ["../esbuild/mocks/linaria/index.ts"],
            // Externals
            "react": ["../esbuild/externals/react/index.js"],
            "react-dom": ["../esbuild/externals/react-dom/index.js"],
            "react-dom/unstable-native-dependencies": [
                "../esbuild/externals/react-dom/unstable-native-dependencies/index.js"
            ],
            "react-dom/server": ["../esbuild/externals/react-dom/server/index.js"],
            // Aliases
            "library/*": ["../../../library/src/*"],
            "test/features": ["../test/features.ts"],
            // (10 more lines)
        }
    }
}

// tsconfig.prod.json includes externals + aliases
{
    "extends": "../tsconfig.json",
    "compilerOptions": {
        "paths": {
            // Externals
            "react": ["../esbuild/externals/react/index.js"],
            "react-dom": ["../esbuild/externals/react-dom/index.js"],
            "react-dom/unstable-native-dependencies": [
                "../esbuild/externals/react-dom/unstable-native-dependencies/index.js"
            ],
            "react-dom/server": ["../esbuild/externals/react-dom/server/index.js"],
            // Aliases
            "library/*": ["../../../library/src/*"],
            "test/features": ["../test/features.ts"],
            // (10 more lines)
        }
    }
}

// The parent ../tsconfig.json only includes aliases
{
    "compilerOptions": {
        "paths": {
            // Aliases
            "library/*": ["../../../library/src/*"],
            "test/features": ["../test/features.ts"],
            // (10 more lines)
        }
    }
}

We have to duplicate all these paths across all files (because you can’t extend the compilerOptions.paths field – if doesn’t merge with the parent’s compilerOptions.paths field but overrides it). This is fairly inconvenient.

Having a tsconfigRaw field in the build API would allow us to generate a virtual tsconfig.json every time ESBuild runs – and add paths as needed.

[evanw]

Thanks for describing your use case in detail. I understand why you might want a virtual file here. In case it helps, another approach is to write out the generated JSON to an actual file and use the tsconfig setting. I mention this because it doesn't sound like you tried this from your description. Does this work for you?

[iamakulov]

Yeah, that’d definitely work as well! Writing out temporary files is a bit less convenient than simply passing a string, but if you prefer to not implement tsconfigRaw, the temp file approach would be 100% suitable.

[iamakulov]

Okay, apologies for spending your attention on this – I figured out how to implement what I wanted through resolve plugins! Closing this.