use filter to drop items then mutuate with map

gatsby-config.js

@@ -12,7 +12,7 @@ AWS.config.update({
 const getValidFiles = function(metadata) {
   file_keys = ["File_1", "File_2", "File_3", "File_4", "File_5"]
   return file_keys.map(key => {
-    if (metadata[key] != "" && metadata[key].endsWith(".mp3")) {
+    if (metadata[key] != "" && (metadata[key].endsWith(".mp3") || metadata[key].endsWith(".mpg"))) {
       return metadata[key]
     }
   })
@@ -133,7 +133,7 @@ module.exports = {
             serialize: ({
               query: { site, imageSharp, allS3Object, allJson },
             }) => {
-              return allJson.edges.map(({ node }) => {
+              return allJson.edges.filter(({ node }) => {
                 S3Obj = allS3Object.edges.filter(s3node => {
                   var s3node = s3node.node
                   // get a list of files from the JSON blob
@@ -144,7 +144,19 @@ module.exports = {
                   )
                   return thing[0]
                 })[0]
-                if (S3Obj !== undefined) {
+                return S3Obj !== undefined
+              }).map(({ node }) => {
+                S3Obj = allS3Object.edges.filter(s3node => {
+                  var s3node = s3node.node
+                  // get a list of files from the JSON blob
+                  validMediaFiles = getValidFiles(node)
+                  //
+                  var thing = validMediaFiles.filter(file =>
+                    s3node.Key.endsWith(file)
+                  )
+                  return thing[0]
+                })[0]
+
                   var S3ObjNode = S3Obj.node
                   var s3URL = `https://${S3ObjNode.Name}.s3.amazonaws.com/${S3ObjNode.Key}`
                   var description = node.Description
@@ -191,12 +203,12 @@ module.exports = {
                       }
                     ],
                   }
-                }
+
               })
             },
             query: `
                 {
-                  allS3Object(filter: {Key: {regex: "/[mp3]$/"}}) {
+                  allS3Object(filter: {Key: {regex: "/[mp3|mpg]$/"}}) {
                     edges {
                       node {
                         Key