Options from extended tsconfig.json are ignored

[wangweixuan]

What happens and why it is wrong

When parsing tsconfig.json, the options are overridden using a naive merge method before they are actually parsed. This leads to certain options (e.g. module) extended from a base tsconfig being ignored unexpectedly and unconditionally.

rollup-plugin-typescript2/src/parse-tsconfig.ts

Lines 45 to 50 in 6b0225a

	const mergedConfig = {};
	_.merge(mergedConfig, getOptionsDefaults(), pluginOptions.tsconfigDefaults, loadedConfig, pluginOptions.tsconfigOverride);
	const preParsedTsConfig = tsModule.parseJsonConfigFileContent(mergedConfig, tsModule.sys, baseDir, getOptionsOverrides(pluginOptions), configFileName);
	const compilerOptionsOverride = getOptionsOverrides(pluginOptions, preParsedTsConfig);
	const parsedTsConfig = tsModule.parseJsonConfigFileContent(mergedConfig, tsModule.sys, baseDir, compilerOptionsOverride, configFileName);

Versions

All latest.

tsconfig.json

{
  "extends": "./tsconfig.base"
}

tsconfig.base.json

{
  "compilerOptions": {
    "module": "esnext"
  }
}

plugin output with verbosity 3

// truncated
rpt2: parsed tsconfig: {
    "options": {
        "module": 5,                                // UNEXPECTED
        "configFilePath": "/path/to/tsconfig.json",
        // truncated
    },
    // truncated
    "raw": {
        "compilerOptions": {
            "module": "ES2015"                      // UNEXPECTED
        },
        "extends": "./tsconfig.base",
        "compileOnSave": false
    },
    // truncated
}
// truncated

[ezolenko]

Yep, only affects module. Should be fixed in master now

[ezolenko]

Fixed in 0.19.2