feat: add respectDnt option

README.md

@@ -78,6 +78,7 @@ _NOTE: By default, this plugin only generates output when run in production mode
 | `cookieDomain`    | (optional) Specify cookie domain.                                                                                                                                                                                                                                                                                  |
 | `localScript`     | (optional) If set, load local `piwik.js` script from the given path, instead of loading it from your `matomoUrl`.                                                                                                                                                                                                  |
 | `trackLoad`       | (optional) If true, it will track the loading of the matomo library. Defaults to `true`.                                                                                                                                                                                                                           |
+| `respectDnt`      |  (optional) If false, will load all scripts without respecting user preference to `Do Not Track` on browsers.  Defaults to `true`.                                                                                                                                                                                 |
 | `dev`             | (optional) Activate dev mode by setting to `true`. Will load all scripts despite not running in `production` environment. Ignores your local browser's DNT header too. Outputs some information in console about what it is doing. Useful for local testing but careful: all hits will be send like in production. |
 
 ```js

src/__tests__/gatsby-ssr.js

@@ -92,6 +92,14 @@ describe('gatsby-plugin-google-analytics', () => {
           const result = JSON.stringify(setPostBodyComponents.mock.calls[0][0])
           expect(result).toMatch(/TEST_LOCAL_SCRIPT/)
         })
+
+        it('sets respectDnt to false', () => {
+          const { setPostBodyComponents } = setup({
+            respectDnt: false
+          })
+          const result = JSON.stringify(setPostBodyComponents.mock.calls[0][0])
+          expect(result).not.toMatch(/navigator.doNotTrack/)
+        })
       })
     })
   })

src/gatsby-ssr.js

@@ -11,14 +11,19 @@ function buildTrackingCode(pluginOptions) {
     localScript,
     requireConsent,
     disableCookies,
-    cookieDomain
+    cookieDomain,
+    respectDnt = true
   } = pluginOptions
 
   const script = localScript ? localScript : `${matomoUrl}/${matomoJsScript}`
 
+  const dntCondition = respectDnt
+    ? `!(navigator.doNotTrack === '1' || window.doNotTrack === '1')`
+    : `true`
+
   const html = `
     window.dev = ${dev}
-    if (window.dev === true || !(navigator.doNotTrack === '1' || window.doNotTrack === '1')) {
+    if (window.dev === true || ${dntCondition}) {
       window._paq = window._paq || [];
       ${requireConsent ? "window._paq.push(['requireConsent']);" : ''}
       ${disableCookies ? "window._paq.push(['disableCookies']);" : ''}