Typescript: "target": "es2015" and @types/node (v10.0.0) cause Duplicate identifier errors

[nebrius]

TypeScript Version: 2.8.3 and 2.9.0-dev.20180427

Search Terms:

Within GitHub on this repo: "Node 10", "Node 10.0.0", "Duplicate identifier", "Duplicate Identifier 'URL'"

Code

Sample code (can probably even be an empty file)

console.log();

tsconfig.json:

{
  "compilerOptions": {
    "target": "es2015",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'. */
    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
    "sourceMap": true,                     /* Generates corresponding '.map' file. */
    "outDir": "./dist",                        /* Redirect output structure to the directory. */
    "rootDir": "./src",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */

    /* Strict Type-Checking Options */
    "strict": true,                           /* Enable all strict type-checking options. */
    "noImplicitAny": true,                 /* Raise error on expressions and declarations with an implied 'any' type. */
    "strictNullChecks": true,              /* Enable strict null checks. */
    "strictFunctionTypes": true,           /* Enable strict checking of function types. */
    "noImplicitThis": true,                /* Raise error on 'this' expressions with an implied 'any' type. */
    "alwaysStrict": true,                  /* Parse in strict mode and emit "use strict" for each source file. */

    /* Additional Checks */
    "noUnusedLocals": true,                /* Report errors on unused locals. */
    "noImplicitReturns": true,             /* Report error when not all code paths in function return a value. */

  }
}

Expected behavior:

This should compile without errors

Actual behavior:

I get the following output:

node_modules/@types/node/index.d.ts(2381,15): error TS2300: Duplicate identifier 'URL'.
node_modules/@types/node/index.d.ts(2399,15): error TS2300: Duplicate identifier 'URLSearchParams'.
node_modules/@types/node/index.d.ts(2417,14): error TS2661: Cannot export 'URL'. Only local declarations can be exported from a module.
node_modules/@types/node/index.d.ts(2417,19): error TS2661: Cannot export 'URLSearchParams'. Only local declarations can be exported from a module.
node_modules/typescript/lib/lib.es6.d.ts(19249,11): error TS2300: Duplicate identifier 'URL'.
node_modules/typescript/lib/lib.es6.d.ts(19265,13): error TS2300: Duplicate identifier 'URL'.
node_modules/typescript/lib/lib.es6.d.ts(19272,11): error TS2300: Duplicate identifier 'URLSearchParams'.
node_modules/typescript/lib/lib.es6.d.ts(19299,13): error TS2300: Duplicate identifier 'URLSearchParams'.
node_modules/typescript/lib/lib.es6.d.ts(21585,13): error TS2300: Duplicate identifier 'URL'.
node_modules/typescript/lib/lib.es6.d.ts(21586,13): error TS2300: Duplicate identifier 'URLSearchParams'.
node_modules/typescript/lib/lib.es6.d.ts(22348,11): error TS2300: Duplicate identifier 'URLSearchParams'.

Playground Link:

Related Issues:

[zhenhua-lee]

I encounter this problem last day. The reason is @types/node:

• [email protected] needs @types/[email protected] in devDependencies
• however other module's dependencies (like @types/[email protected]) is @types/node: *
• so my node_modules install 10.0.0

After changing the version to 8.5.5，the proble is fixed.

[DanielRosenwasser]

Wouldn't this be a matter of setting "lib": ["es2017"] to explicitly remove lib.dom.d.ts?

[DanielRosenwasser]

Looks like this should be fixed by https://github.com/DefinitelyTyped/DefinitelyTyped/pull/25356 but is unfortunately not published to npm.

[kgorlick]

Any idea when this will be published?

[nebrius]

TIL about the lib option in tsconfig, that fixed it for now, thanks!

Given that we're just waiting for the DefinitelyTyped update to be published, I think this can be closed now.