feat: add initial options validation

packages/gatsby-plugin-manifest/README.md

@@ -416,6 +416,12 @@ manifest—https://developers.google.com/web/fundamentals/engage-and-retain/web-
 
 For more information see the w3 spec https://www.w3.org/TR/appmanifest/ or Mozilla docs https://developer.mozilla.org/en-US/docs/Web/Manifest.
 
+### Plugin options validation
+
+This plugin validates plugin options set in the `gatsby-config.js`. It validates the options used by the plugin and the entire WebAppManifest spec. To see the exact implemntation of the validator see [src/plugin-options.js](src/plugin-options.js).
+
+The WebAppManifest spec is not stable at the time of writing. This version of the validator adhears the [most recent](https://www.w3.org/TR/2019/WD-appmanifest-20190911/) version of the specification available.
+
 ## Troubleshooting
 
 ### Incompatible library version: sharp.node requires version X or later, but Z provides version Y

packages/gatsby-plugin-manifest/src/__tests__/plugin-options.js

@@ -0,0 +1,161 @@
+const Joi = require(`@hapi/joi`)
+
+const { validOptions } = require(`../plugin-options`)
+
+const allOptionsValid = {
+  name: `GatsbyJS`,
+  short_name: `GatsbyJS`,
+  start_url: `/`,
+  background_color: `#f7f0eb`,
+  display: `standalone`,
+  theme_color: `#a2466c`,
+  cache_busting_mode: `none`,
+  include_favicon: false,
+  theme_color_in_head: false,
+  crossOrigin: `use-credentials`,
+  legacy: false,
+  icon: `src/images/icon.png`,
+  icons: [
+    {
+      src: `/favicons/android-chrome-192x192.png`,
+      sizes: `192x192`,
+      type: `image/png`,
+    },
+    {
+      src: `/favicons/android-chrome-512x512.png`,
+      sizes: `512x512`,
+      type: `image/png`,
+    },
+  ],
+  lang: `en`,
+  localize: [
+    {
+      start_url: `/de/`,
+      lang: `de`,
+      name: `Die coole Anwendung`,
+      short_name: `Coole Anwendung`,
+      description: `Die Anwendung macht coole Dinge und macht Ihr Leben besser.`,
+    },
+  ],
+  icon_options: {
+    purpose: `maskable`,
+  },
+}
+
+const allOptionsInvalid = {
+  cache_busting_mode: false,
+  include_favicon: `no`,
+  theme_color_in_head: `no`,
+  crossOrigin: `allow`,
+  legacy: `false`,
+  icon: `bob`,
+  icons: [
+    `/favicons/android-chrome-192x192.png`,
+    `/favicons/android-chrome-512x512.png`,
+  ],
+  lang: `en`,
+  localize: {
+    start_url: `/de/`,
+    lang: `de`,
+    name: `Die coole Anwendung`,
+    short_name: `Coole Anwendung`,
+    description: `Die Anwendung macht coole Dinge und macht Ihr Leben besser.`,
+  },
+  icon_options: [{ key: `purpose`, value: `maskable` }],
+}
+
+describe(`Options validation`, () => {
+  const reporter = {
+    panic: jest.fn(),
+  }
+
+  beforeEach(() => {
+    reporter.panic.mockClear()
+  })
+
+  afterEach(() => {
+    expect.hasAssertions()
+  })
+
+  const schema = validOptions(Joi)
+
+  it(`Passes with valid options`, () => {
+    expect(schema.validate(allOptionsValid)).resolves.toEqual(
+      expect.any(Object)
+    )
+  })
+
+  it(`Fails with missing required options`, async () => {
+    try {
+      await schema.validate({})
+    } catch (e) {
+      expect(e.name).toBe(`ValidationError`)
+    }
+  })
+
+  it(`Fails with empty options`, async () => {
+    try {
+      await schema.validate({
+        name: ``,
+        short_name: ``,
+      })
+    } catch (e) {
+      expect(e.details).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            message: expect.stringContaining(`is not allowed to be empty`),
+          }),
+        ])
+      )
+    }
+  })
+
+  it(`Fails with options of wrong types`, async () => {
+    try {
+      await schema.validate(allOptionsInvalid)
+    } catch (e) {
+      expect(e.details).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            message: expect.stringContaining(`must be a`),
+          }),
+        ])
+      )
+    }
+  })
+
+  it(`Fails if either or both icon or icons don't exist`, async () => {
+    try {
+      await schema.validate({})
+    } catch (e) {
+      expect(e.details).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            message: expect.stringContaining(
+              `must contain at least one of [icon, icons]`
+            ),
+          }),
+        ])
+      )
+    }
+  })
+
+  it(`Fails if lang isn't included with the use of localize`, async () => {
+    try {
+      let brokeOptions = { ...allOptionsValid }
+      delete brokeOptions.lang
+      await schema.validate(brokeOptions)
+    } catch (e) {
+      expect(e.details).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            context: expect.objectContaining({
+              main: expect.stringContaining(`localize`),
+              peer: expect.stringContaining(`lang`),
+            }),
+          }),
+        ])
+      )
+    }
+  })
+})

packages/gatsby-plugin-manifest/src/gatsby-node.js

@@ -3,6 +3,7 @@ import path from "path"
 import sharp from "./safe-sharp"
 import { createContentDigest, cpuCoreCount } from "gatsby-core-utils"
 import { defaultIcons, doesIconExist, addDigestToPath } from "./common"
+import { validOptions } from "./plugin-options"
 
 sharp.simd(true)
 
@@ -196,3 +197,5 @@ const makeManifest = async (cache, reporter, pluginOptions) => {
     JSON.stringify(manifest)
   )
 }
+
+exports.validatePluginOptions = ({ validator }) => validOptions(validator)