Merge pull request #172 from observablehq/file-attachment-url-strings

File attachment URL strings (3.3.2)

Author: jashkenas

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@observablehq/stdlib",
-  "version": "3.3.1",
+  "version": "3.3.2",
   "license": "ISC",
   "main": "dist/stdlib.js",
   "module": "src/index.js",

src/fileAttachment.js

@@ -12,7 +12,7 @@ class FileAttachment {
     });
   }
   async url() {
-    return this._url;
+    return (await this._url) + "";
   }
   async blob() {
     return (await remote_fetch(this)).blob();

test/fileAttachments-test.js

@@ -6,3 +6,23 @@ test("FileAttachments is exported by stdlib", t => {
   t.equal(FileAttachments.name, "FileAttachments");
   t.end();
 });
+
+test("FileAttachment ensures that URLs are strings", async t => {
+  const fileAttachments = FileAttachments((name) =>
+    new URL(`https://example.com/${name}.js`)
+  );
+  const file = fileAttachments("filename");
+  t.equal(file.constructor.name, "FileAttachment");
+  t.equal(await file.url(), "https://example.com/filename.js");
+  t.end();
+});
+
+test("FileAttachment works with Promises that resolve to URLs", async t => {
+  const fileAttachments = FileAttachments(async (name) =>
+    new URL(`https://example.com/${name}.js`)
+  );
+  const file = fileAttachments("otherfile");
+  t.equal(file.constructor.name, "FileAttachment");
+  t.equal(await file.url(), "https://example.com/otherfile.js");
+  t.end();
+});