Improve errors for invalid data passed to createPage fixes #3771

packages/gatsby/src/redux/__tests__/__snapshots__/pages.js.snap

@@ -1,5 +1,11 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`Add pages Fails if component path is missing 1`] = `"The plugin \\"test\\" must set the absolute path to the page component when create creating a page"`;
+
+exports[`Add pages Fails if path is missing 1`] = `"The plugin \\"test\\" must set the page path when creating a page"`;
+
+exports[`Add pages Fails if the component path isn't absolute 1`] = `"The plugin \\"test\\" must set the absolute path to the page component when create creating a page"`;
+
 exports[`Add pages allows you to add multiple pages 1`] = `
 Array [
  Object {

packages/gatsby/src/redux/__tests__/pages.js

@@ -21,6 +21,37 @@ describe(`Add pages`, () => {
  expect(state).toMatchSnapshot()
  })
 
+ it(`Fails if path is missing`, () => {
+ const action = actions.createPage(
+ {
+ component: `/whatever/index.js`,
+ },
+ { id: `test`, name: `test` }
+ )
+ expect(action).toMatchSnapshot()
+ })
+
+ it(`Fails if component path is missing`, () => {
+ const action = actions.createPage(
+ {
+ path: `/whatever/`,
+ },
+ { id: `test`, name: `test` }
+ )
+ expect(action).toMatchSnapshot()
+ })
+
+ it(`Fails if the component path isn't absolute`, () => {
+ const action = actions.createPage(
+ {
+ path: `/whatever/`,
+ component: `cheese.js`,
+ },
+ { id: `test`, name: `test` }
+ )
+ expect(action).toMatchSnapshot()
+ })
+
  it(`adds an initial forward slash if the user doesn't`, () => {
  const action = actions.createPage(
  {

packages/gatsby/src/redux/actions.js

@@ -104,6 +104,45 @@ const pascalCase = _.flow(_.camelCase, _.upperFirst)
  * })
  */
 actions.createPage = (page: PageInput, plugin?: Plugin, traceId?: string) => {
+ let noPageOrComponent = false
+ let name = `The plugin "${plugin.name}"`
+ if (plugin.name === `default-site-plugin`) {
+ name = `Your site's "gatsby-node.js"`
+ }
+ if (!page.path) {
+ const message = `${name} must set the page path when creating a page`
+ // Don't log out when testing
+ if (!process.env.NODE_ENV === `test`) {
+ console.log(chalk.bold.red(message))
+ console.log(``)
+ console.log(page)
+ } else {
+ return message
+ }
+ noPageOrComponent = true
+ }
+
+ if (!page.component || !path.isAbsolute(page.component)) {
+ const message = `${name} must set the absolute path to the page component when create creating a page`
+ // Don't log out when testing
+ if (!process.env.NODE_ENV === `test`) {
+ console.log(chalk.bold.red(message))
+ console.log(``)
+ console.log(page)
+ } else {
+ return message
+ }
+ noPageOrComponent = true
+ }
+
+ if (noPageOrComponent) {
+ console.log(``)
+ console.log(
+ `See the documentation for createPage https://www.gatsbyjs.org/docs/bound-action-creators/#createPage`
+ )
+ process.exit(1)
+ }
+
  let jsonName = `${_.kebabCase(page.path)}.json`
  let internalComponentName = `Component${pascalCase(page.path)}`