This patch in conjunction with adding asset.json to assetExts allows JSON files to be treated as assets. This is helpful in cases where the JSON file is large and would cause too much bloat in the main bundle.
Edit: After experimenting with this more, I found that in my use-case using async imports like import("./foo.json") instead works and splits the .json file out into another bundle. With that strategy this PR isn't necessary, so perhaps it's better to just close this.
Summary
This patch in conjunction with adding
asset.jsontoassetExtsallows JSON files to be treated as assets. This is helpful in cases where the JSON file is large and would cause too much bloat in the main bundle.Perhaps because
jsonwas previously in theassetExtsarray (removed in https://github.com/facebook/metro/pull/593) it was necessary to have a special code path for transforming.jsonfiles rather than letting standard asset transformation take priority. However this logic prevents large JSON files from being treated as assets (i.e. not included in the bundle) even when using a custom extension like.asset.json. There is a test forasset.jsonthat hints this should be supported, but the transform prevents it from working in practice (see https://github.com/facebook/metro/blob/412771475c540b6f85d75d9dcd5a39a6e0753582/packages/metro-resolver/src/__tests__/assets-test.js#L67).Edit: After experimenting with this more, I found that in my use-case using async imports like
import("./foo.json")instead works and splits the.jsonfile out into another bundle. With that strategy this PR isn't necessary, so perhaps it's better to just close this.Changelog:
Test plan