Fix license fetch from versions if root level license is missing

src/fixtures/pinpoint-npm-info.json

@@ -0,0 +1,35 @@
+{
+  "_id": "pinpoint",
+  "name": "pinpoint",
+  "description": "Pinpoint test fixture",
+  "homepage": "https://example.com/pinpoint",
+  "author": {
+    "name": "Fixture Author"
+  },
+  "time": {
+    "created": "2016-01-01T00:00:00.000Z",
+    "modified": "2018-01-01T00:00:00.000Z"
+  },
+  "maintainers": [
+    {
+      "name": "fixture-maintainer"
+    }
+  ],
+  "dist-tags": {
+    "latest": "1.1.0"
+  },
+  "versions": {
+    "not-a-version": {
+      "license": "SHOULD_NOT_BE_USED"
+    },
+    "1.0.0": {
+      "license": "MIT"
+    },
+    "1.1.0": {
+      "dependencies": {
+        "left-pad": "^1.3.0"
+      }
+    }
+  },
+  "readme": "# Pinpoint\n\nFixture README"
+}

src/index.test.ts

@@ -1,11 +1,23 @@
 import * as child_process from "child_process"
 import * as mockfs from "fs"
-jest.mock("node-fetch", () => () =>
-  Promise.resolve({
+jest.mock("node-fetch", () => (url: string) => {
+  const readFixture = (requestUrl: string) => {
+    const dep = requestUrl.split("/").pop() || "danger"
+    const fixturePath = `src/fixtures/${dep}-npm-info.json`
+    const fallbackFixturePath = "src/fixtures/danger-npm-info.json"
+
+    try {
+      return JSON.parse(mockfs.readFileSync(fixturePath, "utf8"))
+    } catch (error) {
+      return JSON.parse(mockfs.readFileSync(fallbackFixturePath, "utf8"))
+    }
+  }
+
+  return Promise.resolve({
     ok: true,
-    json: () => Promise.resolve(JSON.parse(mockfs.readFileSync("src/fixtures/danger-npm-info.json", "utf8"))),
+    json: () => Promise.resolve(readFixture(url)),
   })
-)
+})
 
 import yarn, {
   _operateOnSingleDiff,
@@ -155,6 +167,15 @@ describe("npm metadata", () => {
     const npmData = await getNPMMetadataForDep("danger")
     expect(_renderNPMTable({ usedInPackageJSONPaths: ["package.json"], npmData: npmData! })).toMatchSnapshot()
   })
+
+  it("Shows a version license when top-level license is missing", async () => {
+    expect.assertions(2)
+    const npmData = await getNPMMetadataForDep("pinpoint")
+    const rendered = _renderNPMTable({ usedInPackageJSONPaths: ["package.json"], npmData: npmData! })
+
+    expect(rendered).toContain("<b>License:</b> <wbr/>MIT")
+    expect(rendered).not.toContain("<b>NO LICENSE FOUND</b>")
+  })
 })
 
 describe("yarn metadata", () => {

src/index.ts

@@ -171,6 +171,27 @@ export interface PartiallyRenderedNPMMetadata {
   readme: string
 }
 
+const resolvePackageLicense = (npm: any): string | undefined => {
+  if (npm.license) {
+    return npm.license
+  }
+
+  if (!npm.versions) {
+    return undefined
+  }
+
+  const versionsWithLicenses = Object.keys(npm.versions).filter(version => semver.valid(version)).sort(semver.rcompare)
+
+  for (const version of versionsWithLicenses) {
+    const versionMetadata = npm.versions[version]
+    if (versionMetadata && versionMetadata.license) {
+      return versionMetadata.license
+    }
+  }
+
+  return undefined
+}
+
 export const getNPMMetadataForDep = async (
   dep: string,
   npmRegistryUrl?: string,
@@ -209,7 +230,7 @@ export const getNPMMetadataForDep = async (
     tableDeets.push({ break: "row-break" })
 
     // Left
-    const license = npm.license
+    const license = resolvePackageLicense(npm)
     if (license) {
       tableDeets.push({ name: "License", message: license })
     } else {