ESM build import/export are missing file extensions

[dmnsgn]

For proper esm resolution, import/export file need to have a .js extension. Currently the esm index export the following:

export { default as filter } from "./filter";
export { default as flatMap } from "./flatMap";
export { default as interval } from "./interval";
export { default as map } from "./map";
export { default as merge } from "./merge";
export { default as multicast } from "./multicast";
export { default as Observable } from "./observable";
export { default as scan } from "./scan";
export { default as Subject } from "./subject";
export { default as unsubscribe } from "./unsubscribe";

which triggers an error when imported:

Module not found: Error: Can’t resolve ‘./symbols’ in ‘/path/to/node_modules/observable-fns/dist.esm’

This can be solved by adding .js to all the imports/export in the typescript source files (even if they're refering to .ts files).

[andywer]

Hey @dmnsgn, thanks for sharing! Of course you're right…

Would you by any chance have time to prepare a PR?