refactor in sync with node-fetch

Author: tinovyatkin

index.d.ts

@@ -1,107 +1,120 @@
 // Based on https://github.com/tmpvar/jsdom/blob/aa85b2abf07766ff7bf5c1f6daafb3726f2f2db5/lib/jsdom/living/blob.js
 // (MIT licensed)
 
-const {Readable: ReadableStream} = require('stream');
+const {Readable} = require('stream');
+const {types} = require('util');
 
+/**
+ * @type {WeakMap<Blob, { type: string, buffer: Buffer }}
+ */
 const wm = new WeakMap();
 
 class Blob {
+	/**
+   * The Blob() constructor returns a new Blob object. The content of the blob consists of the concatenation of the values given in the parameter array.
+   * @param {(ArrayBufferLike | ArrayBufferView | Blob | Buffer | string)[]} blobParts
+   * @param {{ type?: string }} [options]
+   */
 	constructor(blobParts = [], options = {type: ''}) {
-		const buffers = [];
-		let size = 0;
-
-		blobParts.forEach(element => {
-			let buffer;
-			if (element instanceof Buffer) {
-				buffer = element;
-			} else if (ArrayBuffer.isView(element)) {
-				buffer = Buffer.from(element.buffer, element.byteOffset, element.byteLength);
-			} else if (element instanceof ArrayBuffer) {
-				buffer = Buffer.from(element);
-			} else if (element instanceof Blob) {
-				buffer = wm.get(element).buffer;
-			} else {
-				buffer = Buffer.from(typeof element === 'string' ? element : String(element));
+		const buffers = blobParts.map(element => {
+			if (Buffer.isBuffer(element)) {
+				return element;
 			}
 
-			size += buffer.length;
-			buffers.push(buffer);
+			if (ArrayBuffer.isView(element)) {
+				return Buffer.from(
+					element.buffer,
+					element.byteOffset,
+					element.byteLength
+				);
+			}
+
+			if (types.isAnyArrayBuffer(element)) {
+				return Buffer.from(element);
+			}
+
+			if (wm.has(element)) {
+				return wm.get(element).buffer;
+			}
+
+			return Buffer.from(
+				typeof element === 'string' ? element : String(element)
+			);
 		});
 
-		const buffer = Buffer.concat(buffers, size);
+		const buffer = Buffer.concat(buffers);
 
-		const type = options.type === undefined ? '' : String(options.type).toLowerCase();
+		const type =
+      options.type === undefined ? '' : String(options.type).toLowerCase();
 
 		wm.set(this, {
 			type: /[^\u0020-\u007E]/.test(type) ? '' : type,
-			size,
 			buffer
 		});
 	}
 
+	/**
+   * The Blob interface's size property returns the size of the Blob in bytes.
+   */
 	get size() {
-		return wm.get(this).size;
+		return wm.get(this).buffer.byteLength;
 	}
 
+	/**
+   * The type property of a Blob object returns the MIME type of the file.
+   */
 	get type() {
 		return wm.get(this).type;
 	}
 
-	text() {
-		return Promise.resolve(wm.get(this).buffer.toString());
+	/**
+   * The text() method in the Blob interface returns a Promise that resolves with a string containing the contents of the blob, interpreted as UTF-8.
+   */
+	async text() {
+		return wm.get(this).buffer.toString();
 	}
 
-	arrayBuffer() {
+	/**
+   * The arrayBuffer() method in the Blob interface returns a Promise that resolves with the contents of the blob as binary data contained in an ArrayBuffer.
+   */
+	async arrayBuffer() {
 		const buf = wm.get(this).buffer;
-		const ab = buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
-		return Promise.resolve(ab);
+		const ab = buf.buffer.slice(
+			buf.byteOffset,
+			buf.byteOffset + buf.byteLength
+		);
+		return ab;
 	}
 
+	/**
+   * The Blob interface's stream() method returns a ReadableStream which upon reading returns the data contained within the Blob.
+   */
 	stream() {
-		const readable = new ReadableStream();
-		readable._read = () => { };
-		readable.push(wm.get(this).buffer);
-		readable.push(null);
-		return readable;
+		return Readable.from(wm.get(this).buffer);
+	}
+
+	get [Symbol.toStringTag]() {
+		return 'Blob';
 	}
 
+	/**
+   * @returns {string}
+   */
 	toString() {
-		return '[object Blob]';
+		return Object.prototype.toString.call(this);
 	}
 
-	slice(...args) {
-		const {size} = this;
-
-		const start = args[0];
-		const end = args[1];
-		let relativeStart;
-		let relativeEnd;
-
-		if (start === undefined) {
-			relativeStart = 0; //
-		} else if (start < 0) {
-			relativeStart = Math.max(size + start, 0); //
-		} else {
-			relativeStart = Math.min(start, size);
-		}
-
-		if (end === undefined) {
-			relativeEnd = size; //
-		} else if (end < 0) {
-			relativeEnd = Math.max(size + end, 0); //
-		} else {
-			relativeEnd = Math.min(end, size);
-		}
-
-		const span = Math.max(relativeEnd - relativeStart, 0);
-		const slicedBuffer = wm.get(this).buffer.slice(
-			relativeStart,
-			relativeStart + span
-		);
-		const blob = new Blob([], {type: args[2]});
-		const _ = wm.get(blob);
-		_.buffer = slicedBuffer;
-		return blob;
+	/**
+   * The Blob interface's slice() method creates and returns a new Blob object which contains data from a subset of the blob on which it's called.
+   *
+   * @param {number} [start]
+   * @param {number} [end]
+   * @param {string} [contentType]
+   */
+	slice(start, end, contentType) {
+		return new Blob([wm
+			.get(this)
+			.buffer.subarray(start, end)], {type: contentType});
 	}
 }
 
@@ -111,11 +124,4 @@ Object.defineProperties(Blob.prototype, {
 	slice: {enumerable: true}
 });
 
-Object.defineProperty(Blob.prototype, Symbol.toStringTag, {
-	value: 'Blob',
-	writable: false,
-	enumerable: false,
-	configurable: true
-});
-
 module.exports = Blob;

index.js

@@ -11,15 +11,16 @@
     "lint": "xo",
     "test": "xo && ava",
     "report": "nyc ava",
-    "coverage": "nyc --reporter json --reporter text ava && codecov -f coverage/coverage-final.json"
+    "coverage": "nyc --reporter json --reporter text ava && codecov -f coverage/coverage-final.json",
+    "prepublishOnly": "npx typescript --declaration --emitDeclarationOnly --allowJs index.js"
   },
   "repository": "https://github.com/node-fetch/fetch-blob.git",
   "keywords": [
     "blob",
     "node-fetch"
   ],
   "engines": {
-    "node": ">=6"
+    "node": ">=10.17"
   },
   "author": "David Frank",
   "license": "MIT",
@@ -36,14 +37,16 @@
     "xo": "^0.30.0"
   },
   "xo": {
+    "rules": {
+      "node/no-unsupported-features/node-builtins": 0
+    },
     "overrides": [
       {
         "files": "test.js",
         "rules": {
-          "node/no-unsupported-features/es-syntax": 0,
-          "node/no-unsupported-features/node-builtins": 0
+          "node/no-unsupported-features/es-syntax": 0
         }
       }
     ]
   }
-}
+}