remix-project/libs/remix-solidity/tsconfig.json

{
    "extends": "../../tsconfig.json",
    "include": ["src", "index.ts"],
    "compilerOptions": {
      "target": "es6",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */
      "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
      "lib": ["dom", "es2018"],                 /* Specify library files to be included in the compilation. */
      "types": ["node"],
      "declaration": true,                      /* Generates corresponding '.d.ts' file. */
      "sourceMap": true,                        /* Generates corresponding '.map' file. */
      /* Strict Type-Checking Options */
      "strict": true,                           /* Enable all strict type-checking options. */
      "noImplicitAny": false,
      "typeRoots": [
        "./@types",
        "./node_modules/@types"
      ]
    }
  }