refactor code duplication

Author: janmonschke

packages/gatsby-remark-copy-linked-files/src/index.js

@@ -206,127 +206,65 @@ module.exports = (
   visit(markdownAST, `html`, node => {
     const $ = cheerio.load(node.value)
 
-    // Handle Images
-    const imageRefs = []
-    $(`img`).each(function() {
-      try {
-        if (isRelativeUrl($(this).attr(`src`))) {
-          imageRefs.push($(this))
-        }
-      } catch (err) {
-        // Ignore
-      }
-    })
-
-    for (let thisImg of imageRefs) {
+    function processUrl({ url }) {
       try {
-        const ext = thisImg
-          .attr(`src`)
-          .split(`.`)
-          .pop()
-        if (!options.ignoreFileExtensions.includes(ext)) {
-          generateImagesAndUpdateNode(thisImg, node)
-        }
-      } catch (err) {
-        // Ignore
-      }
-    }
-
-    // Handle video tags.
-    const videoRefs = []
-    $(`video source, video`).each(function() {
-      try {
-        if (isRelativeUrl($(this).attr(`src`))) {
-          videoRefs.push($(this))
-        }
-      } catch (err) {
-        // Ignore
-      }
-    })
-
-    for (let thisVideo of videoRefs) {
-      try {
-        const ext = thisVideo
-          .attr(`src`)
-          .split(`.`)
-          .pop()
+        const ext = url.split(`.`).pop()
         if (!options.ignoreFileExtensions.includes(ext)) {
           // The link object will be modified to the new location so we'll
           // use that data to update our ref
-          const link = { url: thisVideo.attr(`src`) }
+          const link = { url }
           visitor(link)
-          node.value = node.value.replace(
-            new RegExp(thisVideo.attr(`src`), `g`),
-            link.url
-          )
+          node.value = node.value.replace(new RegExp(url, `g`), link.url)
         }
       } catch (err) {
         // Ignore
       }
     }
 
-    // Handle audio tags.
-    const audioRefs = []
-    $(`audio source`).each(function() {
-      try {
-        if (isRelativeUrl($(this).attr(`src`))) {
-          audioRefs.push($(this))
-        }
-      } catch (err) {
-        // Ignore
-      }
-    })
-
-    for (let thisAudio of audioRefs) {
-      try {
-        const ext = thisAudio
-          .attr(`src`)
-          .split(`.`)
-          .pop()
-        if (!options.ignoreFileExtensions.includes(ext)) {
-          const link = { url: thisAudio.attr(`src`) }
-          visitor(link)
-          node.value = node.value.replace(
-            new RegExp(thisAudio.attr(`src`), `g`),
-            link.url
-          )
-        }
-      } catch (err) {
-        // Ignore
-      }
+    // extracts all elements that have the provided url attribute
+    function extractUrlAttributeAndElement(selection, attribute) {
+      return (
+        selection
+          // extract the elements that have the attribute
+          .map(function() {
+            const element = $(this)
+            const url = $(this).attr(attribute)
+            if (url && isRelativeUrl(url)) {
+              return { url, element }
+            }
+            return undefined
+          })
+          // cheerio object -> array
+          .toArray()
+          // filter out empty or undefined values
+          .filter(Boolean)
+      )
     }
 
-    // Handle a tags.
-    const aRefs = []
-    $(`a`).each(function() {
-      try {
-        if (isRelativeUrl($(this).attr(`href`))) {
-          aRefs.push($(this))
+    // Handle Images
+    extractUrlAttributeAndElement($(`img`), `src`).forEach(
+      ({ url, element }) => {
+        try {
+          const ext = url.split(`.`).pop()
+          if (!options.ignoreFileExtensions.includes(ext)) {
+            generateImagesAndUpdateNode(element, node)
+          }
+        } catch (err) {
+          // Ignore
         }
-      } catch (err) {
-        // Ignore
       }
-    })
+    )
 
-    for (let thisATag of aRefs) {
-      try {
-        const ext = thisATag
-          .attr(`href`)
-          .split(`.`)
-          .pop()
-        if (!options.ignoreFileExtensions.includes(ext)) {
-          const link = { url: thisATag.attr(`href`) }
-          visitor(link)
+    // Handle video tags.
+    extractUrlAttributeAndElement($(`video source, video`), `src`).forEach(
+      processUrl
+    )
 
-          node.value = node.value.replace(
-            new RegExp(thisATag.attr(`href`), `g`),
-            link.url
-          )
-        }
-      } catch (err) {
-        // Ignore
-      }
-    }
+    // Handle audio tags.
+    extractUrlAttributeAndElement($(`audio source`), `src`).forEach(processUrl)
+
+    // Handle a tags.
+    extractUrlAttributeAndElement($(`a`), `href`).forEach(processUrl)
 
     return
   })