JSON reports

Every command that takes --format json prints a versioned object. version changes only on breaking changes to the shape, and edgefit diff refuses to compare reports of different versions.

check

edgefit check --format json

{
  "version": 1,
  "summary": { "errors": 1, "warnings": 1 },
  "targets": [
    {
      "key": "workerd",
      "platform": "Cloudflare Workers",
      "conditions": ["workerd", "worker", "browser"],
      "data": "workers-nodejs-compat-matrix@ee58120 (workerd 1.20260929.1), ...",
      "settings": "compatibility_date 2026-09-29, flags: nodejs_compat (from wrangler.jsonc)",
      "notes": [],
      "entry": "src/index.ts",
      "modules": 5,
      "ignored": 0,
      "guarded": [],
      "findings": [
        {
          "category": "unsupported",
          "level": "error",
          "api": "node:fs.watch",
          "target": "workerd",
          "message": "node:fs.watch file watching is not implemented; throws ERR_UNSUPPORTED_OPERATION",
          "detail": "file watching is not implemented; throws ERR_UNSUPPORTED_OPERATION",
          "package": { "name": "chokidar", "version": "4.0.1" },
          "location": { "file": "node_modules/chokidar/index.js", "line": 5, "column": 13 },
          "otherLocations": [],
          "chain": ["src/index.ts", "src/dev/reload.ts", "chokidar"],
          "source": "https://github.com/cloudflare/workerd/tree/v1.20260929.1/src/node/internal/internal_fs_callback.ts"
        }
      ]
    }
  ]
}

guarded has the same shape as findings and holds usages of an API the target lacks, in code that only runs when the API exists (see guarded usages). They are not counted in summary and never fail a check.

Finding

Field	Type	Description
category	string	unsupported, mocked, mismatch, web or unknown
level	string	error or warning
api	string	The API, such as node:fs.watch or require(<expression>)
target	string	The target key
message	string	A full sentence, including the API
detail	string	What is wrong, without the API
package	object | undefined	{ name, version } of the owning package. Absent for your own code
location	object	{ file, line, column }, relative to the root, with / separators
otherLocations	object[]	Other places the same package uses the same API
chain	string[]	Import chain from the entry
source	string | undefined	Link to the runtime source behind a curated result
guarded	true | undefined	Set on entries of guarded

compare

{
  "version": 1,
  "targets": ["workerd", "bun", "deno"],
  "apis": [
    {
      "api": "node:fs.watch",
      "packages": ["chokidar"],
      "results": { "workerd": "unsupported", "bun": "supported", "deno": "supported" }
    }
  ]
}

Each value in results is a category or supported. A target that does not reach the API, or where the finding was ignored or turned off, is left out of results.

diff

{
  "version": 1,
  "targets": ["workerd"],
  "new": [],
  "fixed": [],
  "unchanged": []
}

Each list holds findings in the same shape as check. targets are the head report's targets.