fix esm exports in package.json files

[ushi-as]

Nodejs does not allow to export directories, but it is possible to use subpath patterns to achieve this.

See https://nodejs.org/api/packages.html#subpath-patterns

Reproduce

// test.mjs
import { stringify } from 'csv-stringify/browser/esm/index.js';

$ node test.mjs
node:internal/errors:464
    ErrorCaptureStackTrace(err);
    ^

Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './browser/esm/index.js' is not defined by "exports" in /home/xxx/test/node_modules/csv-stringify/package.json imported from /home/xxx/test/test.mjs
    at new NodeError (node:internal/errors:371:5)
    at throwExportsNotFound (node:internal/modules/esm/resolve:429:9)
    at packageExportsResolve (node:internal/modules/esm/resolve:683:3)
    at packageResolve (node:internal/modules/esm/resolve:853:14)
    at moduleResolve (node:internal/modules/esm/resolve:910:18)
    at defaultResolve (node:internal/modules/esm/resolve:1005:11)
    at ESMLoader.resolve (node:internal/modules/esm/loader:475:30)
    at ESMLoader.getModuleJob (node:internal/modules/esm/loader:245:18)
    at ModuleWrap.<anonymous> (node:internal/modules/esm/module_job:79:40)
    at link (node:internal/modules/esm/module_job:78:36) {
  code: 'ERR_PACKAGE_PATH_NOT_EXPORTED'
}

Node.js v17.1.0

With Node 16 you get a deprecation warning

(node:102) [DEP0148] DeprecationWarning: Use of deprecated folder mapping "./browser/esm/" in the "exports" field module resolution of the package at /home/xxx/test/node_modules/csv-stringify/package.json.
Update this package.json to use a subpath pattern like "./browser/esm/*".

[ivanoats]

This would be great to get into a release, thank you!

[wdavidw]

Thanks, while being aware of the *, I never got any warning/error even after initializing a new project. I will soon release a patch version.