better error messages in js-sdk

packages/js-sdk/src/sandbox/filesystem/index.ts

@@ -147,8 +147,14 @@ export class Filesystem {
     dataOrOpts?: WriteData | FilesystemRequestOpts,
     opts?: FilesystemRequestOpts
   ): Promise<EntryInfo | EntryInfo[]> {
+    if (typeof pathOrFiles !== 'string' && !Array.isArray(pathOrFiles)) {
+      throw new Error('Path or files are required')
+    }
+
     if (typeof pathOrFiles === 'string' && Array.isArray(dataOrOpts)) {
-      throw new Error('Cannot specify path with array of files')
+      throw new Error(
+        'Cannot specify both path and array of files. You have to specify either path and data for a single file or an array for multiple files.'
+      )
     }
 
     const { path, writeOpts, writeFiles } =
@@ -160,6 +166,8 @@ export class Filesystem {
           }
         : { path: undefined, writeOpts: dataOrOpts as FilesystemRequestOpts, writeFiles: pathOrFiles as WriteEntry[] }
 
+    if (writeFiles.length === 0) return [] as EntryInfo[]
+
     const blobs = await Promise.all(writeFiles.map((f) => new Response(f.data).blob()))
 
     const res = await this.envdApi.api.POST('/files', {

packages/js-sdk/tests/sandbox/files/write.test.ts

@@ -17,7 +17,7 @@ sandboxTest('write file', async ({ sandbox }) => {
     })
     .catch((err) => {
       assert.instanceOf(err, Error)
-      assert.include(err.message, 'Cannot read properties of undefined')
+      assert.include(err.message, 'Path or files are required')
     })
 
   const info = await sandbox.files.write(filename, content)
@@ -47,7 +47,7 @@ sandboxTest('write multiple files', async ({ sandbox }) => {
     })
     .catch((err) => {
       assert.instanceOf(err, Error)
-      assert.include(err.message, 'Cannot read properties of undefined')
+      assert.include(err.message, 'Path or files are required')
     })
 
   // Attempt to write with path and file array
@@ -59,7 +59,10 @@ sandboxTest('write multiple files', async ({ sandbox }) => {
     })
     .catch((err) => {
       assert.instanceOf(err, Error)
-      assert.include(err.message, 'Cannot specify path with array of files')
+      assert.include(
+        err.message,
+        'Cannot specify both path and array of files. You have to specify either path and data for a single file or an array for multiple files.'
+      )
     })
 
   // Attempt to write with one file in array