Add: Blob.text() method

lib/jsdom/living/file-api/Blob-impl.js

@@ -90,4 +90,17 @@ exports.implementation = class BlobImpl {
     blob._buffer = slicedBuffer;
     return blob;
   }
+
+  text() {
+    const decoder = new TextDecoder("utf-8");
+    const buffer = this._buffer;
+
+    return new Promise((resolve, reject) => {
+      try {
+        resolve(decoder.decode(buffer));
+      } catch (e) {
+        reject(e);
+      }
+    });
+  }
 };

lib/jsdom/living/file-api/Blob.webidl

@@ -11,6 +11,8 @@ interface Blob {
   Blob slice([Clamp] optional long long start,
             [Clamp] optional long long end,
             optional DOMString contentType);
+
+  Promise<DOMString> text();
 };
 
 enum EndingType { "transparent", "native" };

test/blob-impl.js

@@ -0,0 +1,25 @@
+"use strict";
+const assert = require("node:assert/strict");
+const { describe, it } = require("mocha-sugar-free");
+
+const BlobImpl =
+  require("../lib/jsdom/living/file-api/Blob-impl.js").implementation;
+const { TextDecoder } = require("util");
+global.TextDecoder = TextDecoder;
+
+describe("File-API: Blob-impl.js", () => {
+  it("should return correct test from the blob", done => {
+    const globalObject = {};
+    const blobData = "Hello World";
+    const blobPros = { type: "text/plain" };
+    const blob = new BlobImpl(globalObject, [[blobData], blobPros], {});
+
+    blob
+      .text()
+      .then(text => {
+        assert.strictEqual(text, blobData, 'Blob text should be "Hello World"');
+        done();
+      })
+      .catch(done);
+  });
+});

test/index.js

@@ -1,6 +1,7 @@
 "use strict";
 // This includes all tests that are run using Mocha, including web-platform-tests.
 
+require("./blob-impl.js");
 require("./api/basics.js");
 require("./api/cookies.js");
 require("./api/encoding.js");