feat(gatsby-plugin-offline): Allow configuring Workbox debug m… (#18123)

* Implement initial feature

* improve reliability of regex

* add test + fix default workboxConfig option

* add docs

* Fix unit tests

* fix unit tests (take 2)

Author: vtenfys

packages/gatsby-plugin-offline/README.md

@@ -67,6 +67,8 @@ In `gatsby-plugin-offline` 3.x, the following options are available:
   workbox.routing.registerRoute(customRoute)
   ```
 
+- `debug` specifies whether Workbox should show debugging output in the browser console at runtime. When undefined, defaults to showing debug messages on `localhost` only.
+
 - `workboxConfig` allows you to override the default Workbox options - see [Overriding Workbox configuration](#overriding-workbox-configuration). For example:
 
   ```javascript:title=gatsby-config.js

packages/gatsby-plugin-offline/src/__tests__/gatsby-node.js

@@ -51,6 +51,10 @@ describe(`onPostBuild`, () => {
       swText += text
     },
 
+    writeFileSync(file, text) {
+      swText = text
+    },
+
     createReadStream() {
       return { pipe() {} }
     },
@@ -84,4 +88,22 @@ describe(`onPostBuild`, () => {
 
     expect(swText).toContain(`console.log(\`Hello, world!\`)`)
   })
+
+  it(`configures the Workbox debug option`, async () => {
+    swText = `workbox.setConfig({modulePathPrefix: "workbox-v4.3.1"});`
+
+    await gatsbyNode.onPostBuild(
+      {
+        pathPrefix: ``,
+        reporter: {
+          info(message) {
+            console.log(message)
+          },
+        },
+      },
+      { debug: true }
+    )
+
+    expect(swText).toContain(`debug: true`)
+  })
 })

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

@@ -65,7 +65,12 @@ function getPrecachePages(globs, base) {
 
 exports.onPostBuild = (
   args,
-  { precachePages: precachePagesGlobs = [], appendScript = null, workboxConfig }
+  {
+    precachePages: precachePagesGlobs = [],
+    appendScript = null,
+    debug = undefined,
+    workboxConfig = {},
+  }
 ) => {
   const { pathPrefix, reporter } = args
   const rootDir = `public`
@@ -162,6 +167,16 @@ exports.onPostBuild = (
     .then(({ count, size, warnings }) => {
       if (warnings) warnings.forEach(warning => console.warn(warning))
 
+      if (debug !== undefined) {
+        const swText = fs
+          .readFileSync(swDest, `utf8`)
+          .replace(
+            /(workbox\.setConfig\({modulePathPrefix: "[^"]+")}\);/,
+            `$1, debug: ${JSON.stringify(debug)}});`
+          )
+        fs.writeFileSync(swDest, swText)
+      }
+
       const swAppend = fs
         .readFileSync(`${__dirname}/sw-append.js`, `utf8`)
         .replace(/%pathPrefix%/g, pathPrefix)