Flow’s parser does not understand `export from` attributes (the `with { type: "json" }` syntax).

[sangafabrice]

Flow version: 0.295.0

Expected behavior

According to MDN:

export from supports all features that import supports — for example, import attributes.

So the following should be valid:

/** @file export.js */
export { default } from "./htmlhint.json" with { type: "json" };

/** @file index.js */
import ruleset from "./export.js";

console.log(ruleset);

Running:

node index.js

should output the contents of htmlhint.json as an object:

{ "tagname-lowercase": true }

And processing with Flow should succeed:

npx flow-remove-types --out-file ./export.out.js ./export.js --all

Expected result:

./export.js
 ↳ ./export.out.js

Actual behavior

Flow fails to parse the with { type: "json" } attribute on export from:

./export.js
 ↳ Syntax Error: ';' expected (2:42)
export { default } from "./htmlhint.json" with { type: "json" };
                                          ^
   1: export { default } from "./htmlhint.json" with { type: "json" };

• Link to Try-Flow or Github repo:
  https://flow.org/try/#1N4Igxg9gdgZglgcxALlAIwIZoKYBsD6uEEAztvhgE6UYCe+JADpdhgCYowa5kA0I2KAFcAtiRQAXSkOz9sADwxgJ+NPTbYuQ3BMnTZA+Y2yU4IwRO4A6SFBIrGVDGM7c+h46fNRLuKxJIGWh8MeT0ZfhYlCStpHzNsFBAMIQkIEQwJODAQfiEyfCEoAGsoCAB3KHw4KrBMsAALfAA3KjgsXGxxZC4eAw1m-GhcWn9aY3wWZlc+-g1mbDqJbDYAWglxxJ63AxJi7AlG2lXhXFwZ9z2Do5PRHEoLgyKwTqp1zce8qChFrpIqY41VqmDA+T4gIo-MB-AGrCCMLLQbirRoYGrgor-GDYVYIA7LSgkVZkCQE7q9dxFfIrVbMdJwMjghSeBIhPwYEhkSgqeEmTIQB7bPoAX34kA0SWZAokAAJgDKNFodDLhTKYJR0jKADogKwAegaEhEuAaNRiACsSNAdTLynAJA05TKNsZkNqQJbrSAVQBuXIgZomEhwaBJZoABisACYAJwAVis4ZAwqAA