Fix slice on payloadFromBlob throwing exception

codemod/output/Evaporate.ts

@@ -14,7 +14,7 @@ import {
   removeAtIndex,
   readableFileSize,
   s3EncodedObjectName,
-  getBlobSlice
+  getSupportedBlobSlice
 } from './Utils'
 
 class Evaporate {
@@ -478,10 +478,7 @@ class Evaporate {
         return 'Option readableStreamPartMethod is required when readableStreams is set.'
       }
     } else {
-      if (
-        typeof Blob === 'undefined' ||
-        typeof getBlobSlice() === 'undefined'
-      ) {
+      if (!getSupportedBlobSlice()) {
         return 'Evaporate requires support for Blob [webkitSlice || mozSlice || slice]'
       }
     }

codemod/output/PutPart.ts

@@ -10,7 +10,7 @@ import {
   ERROR,
   PAUSING
 } from './Constants'
-import { getBlobSlice } from './Utils'
+import { getSupportedBlobSlice } from './Utils'
 
 //http://docs.aws.amazon.com/AmazonS3/latest/API/mpUploadUploadPart.html
 class PutPart extends SignedS3AWSRequest {
@@ -299,10 +299,10 @@ class PutPart extends SignedS3AWSRequest {
     // 2nd parameter changed. For example Gecko went from slice(start,length) -> mozSlice(start, end) -> slice(start, end).
     // As of 12/12/12, it seems that the unified 'slice' is the best bet, hence it being first in the list. See
     // https://developer.mozilla.org/en-US/docs/DOM/Blob for more info.
-    const file = this.fileUpload.file
+    const { file } = this.fileUpload
 
-    const slicerFn = getBlobSlice()
-    const blob = slicerFn(this.start, this.end)
+    const slicerKey = getSupportedBlobSlice()
+    const blob = file[slicerKey](this.start, this.end)
 
     if (this.con.computeContentMd5) {
       return new Promise(resolve => {

codemod/output/Utils.ts

@@ -234,12 +234,13 @@ function noOpLogger() {
   }
 }
 
-function getBlobSlice() {
-  return (
-    Blob.prototype.slice ||
-    (Blob as any).prototype.webkitSlice ||
-    (Blob as any).prototype.mozSlice
-  )
+function getSupportedBlobSlice() {
+  if (typeof Blob === 'undefined') {
+    return null
+  }
+
+  const blobProperties = Object.keys(Blob.prototype)
+  return blobProperties.find(key => key.toLowerCase().includes('slice'))
 }
 
 export {
@@ -260,5 +261,5 @@ export {
   removeAtIndex,
   readableFileSize,
   noOpLogger,
-  getBlobSlice
+  getSupportedBlobSlice
 }