fix(gatsby): Support numbers in navigate function

e2e-tests/development-runtime/cypress/integration/navigation/linking.js

@@ -33,6 +33,14 @@ describe(`navigation`, () => {
     cy.location(`pathname`).should(`equal`, `/`)
   })
 
+  it(`can navigate using numbers`, () => {
+    cy.getTestElement(`page-two`).click().waitForRouteChange()
+
+    cy.getTestElement(`back-by-number`).click()
+
+    cy.location(`pathname`).should(`equal`, `/`)
+  })
+
   describe(`relative links`, () => {
     it(`can navigate to a subdirectory`, () => {
       cy.getTestElement(`subdir-link`)

e2e-tests/development-runtime/src/pages/page-2.js

@@ -3,6 +3,7 @@ import { Link } from "gatsby"
 
 import Layout from "../components/layout"
 import SEO from "../components/seo"
+import { navigate } from "gatsby"
 
 const SecondPage = () => (
   <Layout>
@@ -12,6 +13,9 @@ const SecondPage = () => (
     <Link to="/" data-testid="back-button">
       Go back to the homepage
     </Link>
+    <button data-testid="back-by-number" onClick={() => navigate(-1)}>
+      Navigate by number back
+    </button>
   </Layout>
 )
 

packages/gatsby-link/src/index.js

@@ -43,6 +43,9 @@ function absolutify(path, current) {
 }
 
 const rewriteLinkPath = (path, relativeTo) => {
+  if (typeof path === `number`) {
+    return path
+  }
   if (!isLocalLink(path)) {
     return path
   }

packages/gatsby/cache-dir/navigation.js

@@ -47,6 +47,14 @@ const onRouteUpdate = (location, prevLocation) => {
 }
 
 const navigate = (to, options = {}) => {
+  // Support forward/backward navigation with numbers
+  // navigate(-2) (jumps back 2 history steps)
+  // navigate(2)  (jumps forward 2 history steps)
+  if (typeof to === `number`) {
+    globalHistory.navigate(to)
+    return
+  }
+
   let { pathname } = parsePath(to)
   const redirect = redirectMap[pathname]