[0.19.0][Regression] latest release has broken typescript types

[AviVahl]

Saw this issue in our downstream project.
Got broken by #244

Steps to reproduce:

mkdir mixpanel-type-issue
cd mixpanel-type-issue
npm init -y
npm pkg set type=module
npm i mixpanel typescript
npx tsc --init --skipLibCheck false
echo "import mixpanel from 'mixpanel'; mixpanel.init('token');" > main.ts
npx tsc --noEmit

Results in:

node_modules/mixpanel/lib/flags/local_flags.d.ts:6:10 - error TS2305: Module '"../mixpanel-node"' has no exported member 'CustomLogger'.

6 import { CustomLogger } from '../mixpanel-node';
           ~~~~~~~~~~~~

node_modules/mixpanel/lib/flags/remote_flags.d.ts:5:10 - error TS2305: Module '"../mixpanel-node"' has no exported member 'CustomLogger'.

5 import { CustomLogger } from '../mixpanel-node'
           ~~~~~~~~~~~~

node_modules/mixpanel/lib/mixpanel-node.d.ts:5:15 - error TS2451: Cannot redeclare block-scoped variable 'mixpanel'.

5 declare const mixpanel: mixpanel.Mixpanel;
                ~~~~~~~~

node_modules/mixpanel/lib/mixpanel-node.d.ts:5:25 - error TS2503: Cannot find namespace 'mixpanel'.

5 declare const mixpanel: mixpanel.Mixpanel;
                          ~~~~~~~~

node_modules/mixpanel/lib/mixpanel-node.d.ts:7:19 - error TS2451: Cannot redeclare block-scoped variable 'mixpanel'.

7 declare namespace mixpanel {
                    ~~~~~~~~

node_modules/mixpanel/lib/mixpanel-node.d.ts:167:85 - error TS1194: Export declarations are not permitted in a namespace.

167   export { LocalFlagsConfig, RemoteFlagsConfig, FlagContext, SelectedVariant } from './flags/types';
                                                                                        ~~~~~~~~~~~~~~~

node_modules/mixpanel/lib/mixpanel-node.d.ts:168:56 - error TS1194: Export declarations are not permitted in a namespace.

168   export { default as LocalFeatureFlagsProvider } from './flags/local_flags';
                                                           ~~~~~~~~~~~~~~~~~~~~~

node_modules/mixpanel/lib/mixpanel-node.d.ts:169:57 - error TS1194: Export declarations are not permitted in a namespace.

169   export { default as RemoteFeatureFlagsProvider } from './flags/remote_flags';
                                                            ~~~~~~~~~~~~~~~~~~~~~~


Found 8 errors in 3 files.

Errors  Files
     1  node_modules/mixpanel/lib/flags/local_flags.d.ts:6
     1  node_modules/mixpanel/lib/flags/remote_flags.d.ts:5
     6  node_modules/mixpanel/lib/mixpanel-node.d.ts:5

Same commands with mixpanel@0.18.1 work and pass type check.

FYI @tdumitrescu

[AviVahl]

Removing:

  // Export feature flags types for convenience
  export { LocalFlagsConfig, RemoteFlagsConfig, FlagContext, SelectedVariant } from './flags/types';
  export { default as LocalFeatureFlagsProvider } from './flags/local_flags';
  export { default as RemoteFeatureFlagsProvider } from './flags/remote_flags';

from node_modules/mixpanel/lib/mixpanel-node.d.ts fixes the issue.

I suggest converting this tiny library to an actual TypeScript library to avoid such issues.
If that's too much work, then at least add some tsconfig.json and validate the types before shipping.

[tdumitrescu]

Sorry about that, thanks for the report. Should be fixed in 0.19.1 published just now, and we added a quick CI typechecking setup. Let us know if there are issues with the patched version.