feat(gatsby-transformer-remark): Allow for multiple different remark …

…sources (#7512)

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This PR allows for having more than one gatsby-transformer-remark plugin. With the addition of the `filter` option, the user can now decide which nodes should be handled by which plugin. For instance, with gatsby-source-filesystem, one could do the following in order to have multiple different markdown sources:

```js
const plugins = [
  {
    resolve: `gatsby-source-filesystem`,
    options: {
      path: `${__dirname}/src/pages`,
      name: `pages`,
    },
  },
  {
    resolve: `gatsby-source-filesystem`,
    options: {
      path: `${__dirname}/src/blog`,
      name: `blog`,
    },
  },
  {
    resolve: `gatsby-transformer-remark`,
    options: {
      filter: node => node.sourceInstanceName === `pages`,
      type: `MarkdownPage`,
    },
  },
  {
    resolve: `gatsby-transformer-remark`,
    options: {
      filter: node => node.sourceInstanceName === `blog`,
      type: `BlogPost`,
    },
  }
]
```

I've also added a `type` option so that these different plugins create GraphQL types with different names.

In the above example, we could expect that our markdown pages might have different frontmatter fields than our blog entries, but having them all under the `MarkdownRemark` type would force us to add filters on fields in order to only retrieve a list of either of them. Having different frontmatter formats would also pollute our GraphiQL documentation.

Co-authored-by: Ward Peeters <ward@coding-tech.com>

packages/gatsby-transformer-remark/README.md

@@ -14,6 +14,11 @@ plugins: [
   {
     resolve: `gatsby-transformer-remark`,
     options: {
+
+      // Defaults to `() => true`
+      filter: node => node.sourceInstanceName === `blog`,
+      // Defaults to `MarkdownRemark`
+      type: `BlogPost`,
       // CommonMark mode (default: true)
       commonmark: true,
       // Footnotes mode (default: true)

packages/gatsby-transformer-remark/package.json

@@ -8,7 +8,6 @@
   },
   "dependencies": {
     "@babel/runtime": "^7.0.0",
-    "bluebird": "^3.5.0",
     "gray-matter": "^4.0.0",
     "hast-util-raw": "^4.0.0",
     "hast-util-to-html": "^4.0.0",

packages/gatsby-transformer-remark/src/__tests__/extend-node.js

@@ -4,7 +4,7 @@ const {
   GraphQLList,
   GraphQLSchema,
 } = require(`gatsby/graphql`)
-const { onCreateNode } = require(`../gatsby-node`)
+const { onCreateNode, setFieldsOnGraphQLNodeType } = require(`../gatsby-node`)
 const {
   inferObjectStructureFromNodes,
 } = require(`../../../gatsby/src/schema/infer-graphql-type`)
@@ -14,7 +14,7 @@ const extendNodeType = require(`../extend-node-type`)
 async function queryResult(
   nodes,
   fragment,
-  { types = [] } = {},
+  { typeName = `MarkdownRemark`, types = [] } = {},
   { additionalParameters = {}, pluginOptions = {} }
 ) {
   const inferredFields = inferObjectStructureFromNodes({
@@ -51,7 +51,7 @@ async function queryResult(
             name: `LISTNODE`,
             type: new GraphQLList(
               new GraphQLObjectType({
-                name: `MarkdownRemark`,
+                name: typeName,
                 fields: markdownRemarkFields,
               })
             ),
@@ -835,3 +835,47 @@ describe(`Headings are generated correctly from schema`, () => {
     }
   )
 })
+
+describe(`Adding fields to the GraphQL schema`, () => {
+  it(`only adds fields when the GraphQL type matches the provided type`, async () => {
+    const getNode = jest.fn()
+    const getNodesByType = jest.fn()
+
+    expect(
+      setFieldsOnGraphQLNodeType({
+        type: { name: `MarkdownRemark` },
+        getNode,
+        getNodesByType,
+      })
+    ).toBeInstanceOf(Promise)
+
+    expect(
+      setFieldsOnGraphQLNodeType(
+        { type: { name: `MarkdownRemark` }, getNode, getNodesByType },
+        { type: `MarkdownRemark` }
+      )
+    ).toBeInstanceOf(Promise)
+
+    expect(
+      setFieldsOnGraphQLNodeType(
+        { type: { name: `MarkdownRemark` }, getNode, getNodesByType },
+        { type: `GatsbyTestType` }
+      )
+    ).toEqual({})
+
+    expect(
+      setFieldsOnGraphQLNodeType(
+        { type: { name: `GatsbyTestType` }, getNode, getNodesByType },
+        { type: `GatsbyTestType` }
+      )
+    ).toBeInstanceOf(Promise)
+
+    expect(
+      setFieldsOnGraphQLNodeType({
+        type: { name: `GatsbyTestType` },
+        getNode,
+        getNodesByType,
+      })
+    ).toEqual({})
+  })
+})

packages/gatsby-transformer-remark/src/__tests__/on-node-create.js

@@ -1,4 +1,3 @@
-const Promise = require(`bluebird`)
 const _ = require(`lodash`)
 
 const onCreateNode = require(`../on-node-create`)
@@ -120,6 +119,50 @@ yadda yadda
 
       expect(parsed.frontmatter.date).toEqual(new Date(date).toJSON())
     })
+
+    it(`Filters nodes with the given filter function, if provided`, async () => {
+      const content = ``
+
+      node.content = content
+      node.sourceInstanceName = `gatsby-test-source`
+
+      const createNode = jest.fn()
+      const createParentChildLink = jest.fn()
+      const actions = { createNode, createParentChildLink }
+      const createNodeId = jest.fn()
+      createNodeId.mockReturnValue(`uuid-from-gatsby`)
+
+      await onCreateNode(
+        {
+          node,
+          loadNodeContent,
+          actions,
+          createNodeId,
+        },
+        {
+          filter: node =>
+            node.sourceInstanceName === `gatsby-other-test-source`,
+        }
+      ).then(() => {
+        expect(createNode).toHaveBeenCalledTimes(0)
+        expect(createParentChildLink).toHaveBeenCalledTimes(0)
+      })
+
+      await onCreateNode(
+        {
+          node,
+          loadNodeContent,
+          actions,
+          createNodeId,
+        },
+        {
+          filter: node => node.sourceInstanceName === `gatsby-test-source`,
+        }
+      ).then(() => {
+        expect(createNode).toHaveBeenCalledTimes(1)
+        expect(createParentChildLink).toHaveBeenCalledTimes(1)
+      })
+    })
   })
 
   describe(`process graphql correctly`, () => {

packages/gatsby-transformer-remark/src/extend-node-type.js

@@ -16,7 +16,6 @@ const toHAST = require(`mdast-util-to-hast`)
 const hastToHTML = require(`hast-util-to-html`)
 const mdastToToc = require(`mdast-util-toc`)
 const mdastToString = require(`mdast-util-to-string`)
-const Promise = require(`bluebird`)
 const unified = require(`unified`)
 const parse = require(`remark-parse`)
 const stringify = require(`remark-stringify`)
@@ -69,6 +68,72 @@ const safeGetCache = ({ getCache, cache }) => id => {
   return getCache(id)
 }
 
+/**
+ * @template T
+ * @param {Array<T>} input
+ * @param {(input: T) => Promise<void>} iterator
+ * @return Promise<void>
+ */
+const eachPromise = (input, iterator) =>
+  input.reduce(
+    (accumulatorPromise, nextValue) =>
+      accumulatorPromise.then(() => void iterator(nextValue)),
+    Promise.resolve()
+  )
+
+const HeadingType = new GraphQLObjectType({
+  name: `MarkdownHeading`,
+  fields: {
+    value: {
+      type: GraphQLString,
+      resolve(heading) {
+        return heading.value
+      },
+    },
+    depth: {
+      type: GraphQLInt,
+      resolve(heading) {
+        return heading.depth
+      },
+    },
+  },
+})
+
+const HeadingLevels = new GraphQLEnumType({
+  name: `HeadingLevels`,
+  values: {
+    h1: { value: 1 },
+    h2: { value: 2 },
+    h3: { value: 3 },
+    h4: { value: 4 },
+    h5: { value: 5 },
+    h6: { value: 6 },
+  },
+})
+
+const ExcerptFormats = new GraphQLEnumType({
+  name: `ExcerptFormats`,
+  values: {
+    PLAIN: { value: `plain` },
+    HTML: { value: `html` },
+  },
+})
+
+const WordCountType = new GraphQLObjectType({
+  name: `wordCount`,
+  fields: {
+    paragraphs: {
+      type: GraphQLInt,
+    },
+    sentences: {
+      type: GraphQLInt,
+    },
+    words: {
+      type: GraphQLInt,
+    },
+  },
+})
+
 /**
  * Map that keeps track of generation of AST to not generate it multiple
  * times in parallel.
@@ -88,29 +153,31 @@ module.exports = (
     reporter,
     ...rest
   },
-  pluginOptions
+  {
+    type: typeName = `MarkdownRemark`,
+    plugins = [],
+    blocks,
+    commonmark = true,
+    footnotes = true,
+    gfm = true,
+    pedantic = true,
+    tableOfContents = {
+      heading: null,
+      maxDepth: 6,
+    },
+    ...grayMatterOptions
+  } = {}
 ) => {
-  if (type.name !== `MarkdownRemark`) {
+  if (type.name !== typeName) {
     return {}
   }
-  pluginsCacheStr = pluginOptions.plugins.map(p => p.name).join(``)
+  pluginsCacheStr = plugins.map(p => p.name).join(``)
   pathPrefixCacheStr = pathPrefix || ``
 
   const getCache = safeGetCache({ cache, getCache: possibleGetCache })
 
   return new Promise((resolve, reject) => {
     // Setup Remark.
-    const {
-      blocks,
-      commonmark = true,
-      footnotes = true,
-      gfm = true,
-      pedantic = true,
-      tableOfContents = {
-        heading: null,
-        maxDepth: 6,
-      },
-    } = pluginOptions
     const tocOptions = tableOfContents
     const remarkOptions = {
       commonmark,
@@ -123,7 +190,7 @@ module.exports = (
     }
     let remark = new Remark().data(`settings`, remarkOptions)
 
-    for (let plugin of pluginOptions.plugins) {
+    for (let plugin of plugins) {
       const requiredPlugin = require(plugin.resolve)
       if (_.isFunction(requiredPlugin.setParserPlugins)) {
         for (let parserPlugin of requiredPlugin.setParserPlugins(
@@ -167,8 +234,8 @@ module.exports = (
       if (process.env.NODE_ENV !== `production` || !fileNodes) {
         fileNodes = getNodesByType(`File`)
       }
-      // Use Bluebird's Promise function "each" to run remark plugins serially.
-      await Promise.each(pluginOptions.plugins, plugin => {
+
+      await eachPromise(plugins, plugin => {
         const requiredPlugin = require(plugin.resolve)
         if (_.isFunction(requiredPlugin.mutateSource)) {
           return requiredPlugin.mutateSource(
@@ -235,8 +302,8 @@ module.exports = (
       if (process.env.NODE_ENV !== `production` || !fileNodes) {
         fileNodes = getNodesByType(`File`)
       }
-      // Use Bluebird's Promise function "each" to run remark plugins serially.
-      await Promise.each(pluginOptions.plugins, plugin => {
+
+      await eachPromise(plugins, plugin => {
         const requiredPlugin = require(plugin.resolve)
         if (_.isFunction(requiredPlugin)) {
           return requiredPlugin(
@@ -448,44 +515,6 @@ module.exports = (
       return text
     }
 
-    const HeadingType = new GraphQLObjectType({
-      name: `MarkdownHeading`,
-      fields: {
-        value: {
-          type: GraphQLString,
-          resolve(heading) {
-            return heading.value
-          },
-        },
-        depth: {
-          type: GraphQLInt,
-          resolve(heading) {
-            return heading.depth
-          },
-        },
-      },
-    })
-
-    const HeadingLevels = new GraphQLEnumType({
-      name: `HeadingLevels`,
-      values: {
-        h1: { value: 1 },
-        h2: { value: 2 },
-        h3: { value: 3 },
-        h4: { value: 4 },
-        h5: { value: 5 },
-        h6: { value: 6 },
-      },
-    })
-
-    const ExcerptFormats = new GraphQLEnumType({
-      name: `ExcerptFormats`,
-      values: {
-        PLAIN: { value: `plain` },
-        HTML: { value: `html` },
-      },
-    })
-
     return resolve({
       html: {
         type: GraphQLString,
@@ -523,7 +552,7 @@ module.exports = (
             format,
             pruneLength,
             truncate,
-            excerptSeparator: pluginOptions.excerpt_separator,
+            excerptSeparator: grayMatterOptions.excerpt_separator,
           })
         },
       },
@@ -543,7 +572,7 @@ module.exports = (
           return getExcerptAst(markdownNode, {
             pruneLength,
             truncate,
-            excerptSeparator: pluginOptions.excerpt_separator,
+            excerptSeparator: grayMatterOptions.excerpt_separator,
           }).then(ast => {
             const strippedAst = stripPosition(_.clone(ast), true)
             return hastReparseRaw(strippedAst)
@@ -602,20 +631,7 @@ module.exports = (
       },
       // TODO add support for non-latin languages https://github.com/wooorm/remark/issues/251#issuecomment-296731071
       wordCount: {
-        type: new GraphQLObjectType({
-          name: `wordCount`,
-          fields: {
-            paragraphs: {
-              type: GraphQLInt,
-            },
-            sentences: {
-              type: GraphQLInt,
-            },
-            words: {
-              type: GraphQLInt,
-            },
-          },
-        }),
+        type: WordCountType,
         resolve(markdownNode) {
           let counts = {}