@uppy/transloadit: ensure fields is not nullish when there no uploaded files

packages/@uppy/transloadit/src/AssemblyOptions.js

@@ -55,20 +55,16 @@ async function getAssemblyOptions (file, options) {
 
   validateParams(assemblyOptions.params)
 
-  return assemblyOptions
-}
-
-function getFields (file, assemblyOptions) {
   const { fields } = assemblyOptions
-  if (fields == null) {
-    return {}
-  }
   if (Array.isArray(fields)) {
-    return Object.fromEntries(
+    assemblyOptions.fields = file == null ? {} : Object.fromEntries(
       fields.map((fieldName) => [fieldName, file.meta[fieldName]]),
     )
+  } else if (fields == null) {
+    assemblyOptions.fields = {}
   }
-  return fields
+
+  return assemblyOptions
 }
 
 /**
@@ -102,8 +98,6 @@ class AssemblyOptions {
           // waiting for the options.
           if (file == null) return undefined
 
-          assemblyOptions.fields = getFields(file, assemblyOptions)
-
           return {
             fileIDs: [file.id],
             options: assemblyOptions,
@@ -118,7 +112,7 @@ class AssemblyOptions {
 
       return [
         {
-          fileIDs: this.files.map((file) => file.id),
+          fileIDs: [],
           options: assemblyOptions,
         },
       ]

packages/@uppy/transloadit/src/index.js

@@ -188,14 +188,12 @@ export default class Transloadit extends BasePlugin {
     return newFile
   }
 
-  #createAssembly (fileIDs, uploadID, options) {
+  #createAssembly (fileIDs, uploadID, assemblyOptions) {
     this.uppy.log('[Transloadit] Create Assembly')
 
     return this.client.createAssembly({
-      params: options.params,
-      fields: options.fields,
+      ...assemblyOptions,
       expectedFiles: fileIDs.length,
-      signature: options.signature,
     }).then(async (newAssembly) => {
       const files = this.uppy.getFiles().filter(({ id }) => fileIDs.includes(id))
       if (files.length !== fileIDs.length) {

packages/@uppy/transloadit/src/index.test.js

@@ -1,3 +1,5 @@
+import { createServer } from 'node:http'
+import { once } from 'node:events'
 import { describe, expect, it } from '@jest/globals'
 import Core from '@uppy/core'
 import Transloadit from './index.js'
@@ -84,4 +86,53 @@ describe('Transloadit', () => {
       expect(uppy.getFile(fileID).progress.uploadStarted).toBe(null)
     })
   })
+
+  it('Can start an assembly with no files and no fields', async () => {
+    const server = createServer((req, res) => {
+      res.setHeader('Access-Control-Allow-Origin', '*')
+      res.setHeader('Access-Control-Allow-Headers', '*')
+      res.setHeader('Content-Type', 'application/json')
+      res.end('{"websocket_url":"about:blank"}')
+    }).listen()
+    await once(server, 'listening')
+    const uppy = new Core({
+      autoProceed: false,
+    })
+    uppy.use(Transloadit, {
+      service: `http://localhost:${server.address().port}`,
+      alwaysRunAssembly: true,
+      params: {
+        auth: { key: 'some auth key string' },
+        template_id: 'some template id string',
+      },
+    })
+
+    await uppy.upload()
+    server.close()
+  })
+
+  it('Can start an assembly with no files and some fields', async () => {
+    const server = createServer((req, res) => {
+      res.setHeader('Access-Control-Allow-Origin', '*')
+      res.setHeader('Access-Control-Allow-Headers', '*')
+      res.setHeader('Content-Type', 'application/json')
+      res.end('{"websocket_url":"about:blank"}')
+    }).listen()
+    await once(server, 'listening')
+    const uppy = new Core({
+      autoProceed: false,
+    })
+    uppy.use(Transloadit, {
+      service: `http://localhost:${server.address().port}`,
+      alwaysRunAssembly: true,
+      params: {
+        auth: { key: 'some auth key string' },
+        template_id: 'some template id string',
+      },
+      fields: ['hasOwnProperty'],
+    })
+
+    await uppy.upload()
+    server.close()
+  })
 })

packages/@uppy/transloadit/types/index.d.ts

@@ -92,13 +92,13 @@ interface AssemblyParameters {
   }
   template_id?: string
   steps?: { [step: string]: Record<string, unknown> }
+  fields?: { [name: string]: number | string }
   notify_url?: string
 }
 
 interface AssemblyOptions {
   params?: AssemblyParameters
   fields?: { [name: string]: number | string } | string[]
-  // TODO (major): move signature into params.auth.
   signature?: string
 }
 
@@ -116,7 +116,7 @@ interface Options extends PluginOptions {
 export type TransloaditOptions = Options &
   (
     | {
-        assemblyOptions?: AssemblyOptions | ((file: UppyFile) => Promise<AssemblyOptions> | AssemblyOptions)
+        assemblyOptions?: AssemblyOptions | ((file?: UppyFile) => Promise<AssemblyOptions> | AssemblyOptions)
         /** @deprecated use `assemblyOptions` instead */
         getAssemblyOptions?: never
         /** @deprecated use `assemblyOptions` instead */
@@ -129,7 +129,7 @@ export type TransloaditOptions = Options &
     | {
         /** @deprecated use `assemblyOptions` instead */
         getAssemblyOptions?: (
-          file: UppyFile
+          file?: UppyFile
         ) => AssemblyOptions | Promise<AssemblyOptions>
         assemblyOptions?: never
         /** @deprecated use `assemblyOptions` instead */

packages/@uppy/transloadit/types/index.test-d.ts

@@ -16,7 +16,7 @@ const validParams = {
   const uppy = new Uppy()
   uppy.use(Transloadit, {
     getAssemblyOptions (file) {
-      expectType<UppyFile>(file)
+      expectType<UppyFile | undefined>(file)
       return { params: validParams }
     },
     waitForEncoding: false,
@@ -39,7 +39,7 @@ const validParams = {
   const uppy = new Uppy()
   uppy.use(Transloadit, {
     async assemblyOptions (file) {
-      expectType<UppyFile>(file)
+      expectType<UppyFile | undefined>(file)
       return { params: validParams }
     },
   })