feat: implement file acceptance validation in utils and integrate with Dropzone component

app/__test__/core/utils.spec.ts

@@ -264,6 +264,35 @@ describe("Core Utils", async () => {
             height: 512,
          });
       });
+
+      test("isFileAccepted", () => {
+         const file = new File([""], "file.txt", {
+            type: "text/plain",
+         });
+         expect(utils.isFileAccepted(file, "text/plain")).toBe(true);
+         expect(utils.isFileAccepted(file, "text/plain,text/html")).toBe(true);
+         expect(utils.isFileAccepted(file, "text/html")).toBe(false);
+
+         {
+            const file = new File([""], "file.jpg", {
+               type: "image/jpeg",
+            });
+            expect(utils.isFileAccepted(file, "image/jpeg")).toBe(true);
+            expect(utils.isFileAccepted(file, "image/jpeg,image/png")).toBe(true);
+            expect(utils.isFileAccepted(file, "image/png")).toBe(false);
+            expect(utils.isFileAccepted(file, "image/*")).toBe(true);
+            expect(utils.isFileAccepted(file, ".jpg")).toBe(true);
+            expect(utils.isFileAccepted(file, ".jpg,.png")).toBe(true);
+            expect(utils.isFileAccepted(file, ".png")).toBe(false);
+         }
+
+         {
+            const file = new File([""], "file.png");
+            expect(utils.isFileAccepted(file, undefined as any)).toBe(true);
+         }
+
+         expect(() => utils.isFileAccepted(null as any, "text/plain")).toThrow();
+      });
    });
 
    describe("dates", () => {

app/src/core/utils/file.ts

@@ -240,3 +240,46 @@ export async function blobToFile(
       lastModified: Date.now(),
    });
 }
+
+export function isFileAccepted(file: File | unknown, _accept: string | string[]): boolean {
+   const accept = Array.isArray(_accept) ? _accept.join(",") : _accept;
+   if (!accept || !accept.trim()) return true; // no restrictions
+   if (!isFile(file)) {
+      throw new Error("Given file is not a File instance");
+   }
+
+   const name = file.name.toLowerCase();
+   const type = (file.type || "").trim().toLowerCase();
+
+   // split on commas, trim whitespace
+   const tokens = accept
+      .split(",")
+      .map((t) => t.trim().toLowerCase())
+      .filter(Boolean);
+
+   // try each token until one matches
+   return tokens.some((token) => {
+      if (token.startsWith(".")) {
+         // extension match, e.g. ".png" or ".tar.gz"
+         return name.endsWith(token);
+      }
+
+      const slashIdx = token.indexOf("/");
+      if (slashIdx !== -1) {
+         const [major, minor] = token.split("/");
+         if (minor === "*") {
+            // wildcard like "image/*"
+            if (!type) return false;
+            const [fMajor] = type.split("/");
+            return fMajor === major;
+         } else {
+            // exact MIME like "image/svg+xml" or "application/pdf"
+            // because of "text/plain;charset=utf-8"
+            return type.startsWith(token);
+         }
+      }
+
+      // unknown token shape, ignore
+      return false;
+   });
+}

app/src/ui/elements/media/Dropzone.tsx

@@ -9,8 +9,8 @@ import {
    useEffect,
    useMemo,
    useRef,
-   useState,
 } from "react";
+import { isFileAccepted } from "bknd/utils";
 import { type FileWithPath, useDropzone } from "./use-dropzone";
 import { checkMaxReached } from "./helper";
 import { DropzoneInner } from "./DropzoneInner";
@@ -173,12 +173,14 @@ export function Dropzone({
 
       return specs.every((spec) => {
          if (spec.kind !== "file") {
-            console.log("not a file", spec.kind);
+            console.warn("file not accepted: not a file", spec.kind);
             return false;
          }
          if (allowedMimeTypes && allowedMimeTypes.length > 0) {
-            console.log("not allowed mimetype", spec.type);
-            return allowedMimeTypes.includes(spec.type);
+            if (!isFileAccepted(i, allowedMimeTypes)) {
+               console.warn("file not accepted: not allowed mimetype", spec.type);
+               return false;
+            }
          }
          return true;
       });