The TypeScript compiler (tsc) provides a showConfig option to view the effective tsconfig.json:

$ node_modules/.bin/tsc --showConfig
{
    "compilerOptions": {
        "target": "es6",
        "typeRoots": [
            "/Users/gh/src/test/node_modules/@types"
        ],
        "lib": [
            "es7"
        ],
        "strictNullChecks": true,
        "noImplicitAny": true
    },
    "files": [
        "./src/foo.ts",
        "./src/bar.ts"
    ]
}

This is helpful for debugging issues with inherited tsconfigs.