Return empty a empty stream for zero sized blob (#86)

Return empty a empty stream for zero sized blob

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
-        node: ["14", "12", engines]
+        node: ["15", "14", "12", engines]
         exclude:
           # On Windows, run tests with only the LTS environments.
           - os: windows-latest
@@ -47,7 +47,6 @@ jobs:
           node-version: ${{steps.get-version.outputs.node}}
 
       - run: npm install
-      - run: npm install domexception
 
       - run: npm run report -- --colors
 

.gitignore

@@ -63,3 +63,4 @@ typings/
 .env
 
 index.d.ts
+from.d.ts

CHANGELOG.md

@@ -1,6 +1,17 @@
 Changelog
 =========
 
+## next
+- Fixed a bug where in BlobDataItem when the file was empty (#86)
+
+## v2.1.2
+- Fixed a bug where `start` in BlobDataItem was undefined (#85)
+
+## v2.1.1
+- Add nullish values checking in Symbol.hasInstance (#82)
+- Add generated typings for from.js file (#80)
+- Updated dev dependencies
+
 ## v2.1.0
 - Fix: .slice has an implementation bug (#54).
 - Added blob backed up by filesystem (#55)

from.js

@@ -1,5 +1,5 @@
 const {statSync, createReadStream} = require('fs');
-const Blob = require('.');
+const Blob = require('./index.js');
 const DOMException = require('domexception');
 
 /**
@@ -23,12 +23,12 @@ class BlobDataItem {
 	constructor(options) {
 		this.size = options.size;
 		this.path = options.path;
-		this.start = options.start;
+		this.start = options.start || 0;
 		this.mtime = options.mtime;
 	}
 
-	// Slicing arguments is validated and formated
+	// Slicing arguments is first validated and formated
-	// by Blob.prototype.slice
+	// to not be out of range by Blob.prototype.slice
 	slice(start, end) {
 		return new BlobDataItem({
 			path: this.path,
@@ -43,6 +43,10 @@ class BlobDataItem {
 			throw new DOMException('The requested file could not be read, typically due to permission problems that have occurred after a reference to a file was acquired.', 'NotReadableError');
 		}
 
+		if (!this.size) {
+			return new Blob().stream();
+		}
+
 		return createReadStream(this.path, {
 			start: this.start,
 			end: this.start + this.size - 1

index.js

@@ -24,7 +24,7 @@ class Blob {
 	 * @param {(ArrayBufferLike | ArrayBufferView | Blob | Buffer | string)[]} blobParts
 	 * @param {{ type?: string }} [options]
 	 */
-	constructor(blobParts = [], options = {type: ''}) {
+	constructor(blobParts = [], options = {}) {
 		let size = 0;
 
 		const parts = blobParts.map(element => {
@@ -41,6 +41,7 @@ class Blob {
 				buffer = Buffer.from(typeof element === 'string' ? element : String(element));
 			}
 
+			// eslint-disable-next-line unicorn/explicit-length-check
 			size += buffer.length || buffer.size || 0;
 			return buffer;
 		});
@@ -148,7 +149,7 @@ class Blob {
 			}
 		}
 
-		const blob = new Blob([], {type});
+		const blob = new Blob([], {type: String(type).toLowerCase()});
 		Object.assign(wm.get(blob), {size: span, parts: blobParts});
 
 		return blob;
@@ -160,6 +161,7 @@ class Blob {
 
 	static [Symbol.hasInstance](object) {
 		return (
+			object &&
 			typeof object === 'object' &&
 			typeof object.stream === 'function' &&
 			object.stream.length === 0 &&

package.json

@@ -1,19 +1,20 @@
 {
     "name": "fetch-blob",
-    "version": "2.1.0",
+    "version": "2.1.2",
     "description": "A Blob implementation in Node.js, originally from node-fetch.",
     "main": "index.js",
     "files": [
         "from.js",
         "index.js",
-        "index.d.ts"
+        "index.d.ts",
+        "from.d.ts"
     ],
     "scripts": {
         "lint": "xo",
         "test": "xo && ava",
         "report": "c8 --reporter json --reporter text ava",
         "coverage": "c8 --reporter json --reporter text ava && codecov -f coverage/coverage-final.json",
-        "prepublishOnly": "tsc --declaration --emitDeclarationOnly --allowJs index.js"
+        "prepublishOnly": "tsc --declaration --emitDeclarationOnly --allowJs index.js from.js"
     },
     "repository": "https://github.com/node-fetch/fetch-blob.git",
     "keywords": [
@@ -29,16 +30,17 @@
         "url": "https://github.com/node-fetch/fetch-blob/issues"
     },
     "homepage": "https://github.com/node-fetch/fetch-blob#readme",
-    "devDependencies": {
-        "ava": "^3.8.2",
-        "c8": "^7.2.0",
-        "codecov": "^3.7.0",
-        "get-stream": "^5.1.0",
-        "node-fetch": "^2.6.0",
-        "typescript": "^3.9.5",
-        "xo": "^0.32.0"
-    },
     "xo": {
+        "rules": {
+            "unicorn/import-index": "off",
+            "import/extensions": [
+                "error",
+                "always",
+                {
+                    "ignorePackages": true
+                }
+            ]
+        },
         "overrides": [
             {
                 "files": "test.js",
@@ -49,7 +51,19 @@
             }
         ]
     },
-    "peerDependencies": {
+    "peerDependenciesMeta": {
-        "domexception": "^2.0.1"
+        "domexception": {
+            "optional": true
+        }
+    },
+    "devDependencies": {
+        "ava": "^3.15.0",
+        "c8": "^7.7.1",
+        "codecov": "^3.8.1",
+        "domexception": "^2.0.1",
+        "get-stream": "^6.0.1",
+        "node-fetch": "^2.6.1",
+        "typescript": "^4.2.4",
+        "xo": "^0.38.2"
     }
 }

test.js

@@ -1,10 +1,10 @@
 const fs = require('fs');
 const test = require('ava');
-const Blob = require('.');
-const blobFrom = require('./from');
 const getStream = require('get-stream');
 const {Response} = require('node-fetch');
 const {TextDecoder} = require('util');
+const Blob = require('./index.js');
+const blobFrom = require('./from.js');
 
 test('new Blob()', t => {
 	const blob = new Blob(); // eslint-disable-line no-unused-vars
@@ -153,10 +153,43 @@ test('blob part backed up by filesystem', async t => {
 
 test('Reading after modified should fail', async t => {
 	const blob = blobFrom('./LICENSE');
-	await new Promise(resolve => setTimeout(resolve, 100));
+	await new Promise(resolve => {
+		setTimeout(resolve, 100);
+	});
 	const now = new Date();
 	// Change modified time
 	fs.utimesSync('./LICENSE', now, now);
 	const error = await blob.text().catch(error => error);
 	t.is(error.name, 'NotReadableError');
 });
+
+test('Reading from the stream created by blobFrom', async t => {
+	const blob = blobFrom('./LICENSE');
+	const expected = await fs.promises.readFile('./LICENSE', 'utf-8');
+
+	const actual = await getStream(blob.stream());
+
+	t.is(actual, expected);
+});
+
+test('Reading empty blobs', async t => {
+	const blob = blobFrom('./LICENSE').slice(0, 0);
+	const actual = await blob.text();
+	t.is(actual, '');
+});
+
+test('Blob-ish class is an instance of Blob', t => {
+	class File {
+		stream() {}
+
+		get [Symbol.toStringTag]() {
+			return 'File';
+		}
+	}
+
+	t.true(new File() instanceof Blob);
+});
+
+test('Instanceof check returns false for nullish values', t => {
+	t.false(null instanceof Blob);
+});