Adding support for stream based on iconv-lite

Author: fguitton

lib/TextDecoder-impl.js

@@ -1,6 +1,7 @@
 "use strict";
 
-const { labelToName, isSupported, decode } = require("./whatwg-encoding");
+const { labelToName, isSupported } = require("./whatwg-encoding");
+const iconvLite = require("iconv-lite");
 
 exports.implementation = class TextDecoderImpl {
   constructor(globalObject, [label, options = {}]) {
@@ -26,16 +27,32 @@ exports.implementation = class TextDecoderImpl {
   }
 
   decode(input, options = {}) {
-    if (options.stream === true) {
-      // TODO: Implement stream support
+    let bytes;
+    if (input === undefined) {
+      bytes = new Uint8Array(0);
+    } else if (input.buffer === undefined) {
+      bytes = Buffer.from(input);
+    } else {
+      bytes = input;
     }
-    try {
-      return decode(input, this._encoding, this._ignoreBOM);
-    } catch (exception) {
-      if (this._errorMode === "fatal") {
-        throw new TypeError(exception);
+
+    let output = "";
+
+    if (options.stream === true) {
+      if (this._decoder === undefined) {
+        this._decoder = iconvLite.decodeStream(this._encoding);
+      }
+      this._decoder.write(input);
+      let chunk;
+      while ((chunk = this._decoder.read()) !== null) {
+        output += chunk;
       }
-      return exception;
+    } else {
+      output = iconvLite.decode(bytes, this._encoding, {
+        stripBOM: !this.ignoreBOM
+      });
     }
+
+    return output;
   }
 };

lib/whatwg-encoding.js

@@ -13,30 +13,22 @@ exports.labelToName = label => {
 };
 
 // https://encoding.spec.whatwg.org/#decode
-exports.decode = (input, fallbackEncodingName, ignoreBOM) => {
+exports.decode = (buffer, fallbackEncodingName) => {
   let encoding = fallbackEncodingName;
   if (!exports.isSupported(encoding)) {
     throw new RangeError(`"${encoding}" is not a supported encoding name`);
   }
 
-  const bomEncoding = exports.getBOMEncoding(input);
+  const bomEncoding = exports.getBOMEncoding(buffer);
   if (bomEncoding !== null) {
     encoding = bomEncoding;
   }
 
   // iconv-lite will strip BOMs for us, so no need to do the stuff the spec does
 
-  const decodeOptions = {
-    stripBOM: !ignoreBOM
-  };
-
-  if (input.buffer !== undefined)
-    return iconvLite.decode(input, encoding, decodeOptions);
-  else
-    return iconvLite.decode(Buffer.from(input), encoding, decodeOptions);
+  return iconvLite.decode(buffer, encoding);
 };
 
-
 // https://encoding.spec.whatwg.org/#encode
 exports.encode = (buffer) => {
   return iconvLite.encode(buffer, "UTF-8")

scripts/get-latest-platform-tests.js

@@ -48,28 +48,33 @@ for (const file of [
   // Missing testharness 'createBuffer' function
   // "textdecoder-copy.any.js",
 
-  // Package 'iconv-lite' does not support 'x-mac-cyrillic'
+  // Package 'iconv-lite' does not support fatal throw and encoding 'x-mac-cyrillic'
   // "textdecoder-fatal-single-byte.any.js",
 
   // Stream support not implemented
+  // Package 'iconv-lite' does not support fatal throw
   // "textdecoder-fatal-streaming.any.js",
 
+  // Package 'iconv-lite' does not support fatal throw
   // "textdecoder-fatal.any.js",
 
+  // Package 'iconv-lite'
   "textdecoder-ignorebom.any.js",
 
-  // Infinite looping
+  // Infinite looping does not support many encodings
   // "textdecoder-labels.any.js",
 
   // Stream support not implemented
+  // Missing testharness 'createBuffer' function
   // "textdecoder-streaming.any.js",
 
-  // "textdecoder-utf16-surrogates.any.js"
+  // Issue with package 'iconv-lite' not converting all inputs properly
+  // "textdecoder-utf16-surrogates.any.js",
 
-  // Package 'iconv-lite' does not support 'x-mac-cyrillic', 'ISO-8859-8-I', 'ISO-2022-JP', 'x-user-defined'
+  // Package 'iconv-lite' does not support encoding 'x-mac-cyrillic', 'ISO-8859-8-I', 'ISO-2022-JP', 'x-user-defined'
   // "textencoder-constructor-non-utf.any.js",
 
-  "textencoder-utf16-surrogates.any.js",
+  "textencoder-utf16-surrogates.any.js"
 
   // Missing testharness 'decode_test' function
   // "unsupported-encodings.any.js"

test/testharness.js

@@ -35,12 +35,12 @@ module.exports = {
     assert.deepStrictEqual([...actual], [...expected]);
   },
 
-  assert_throws(code, func) {
-    assert.throws(func);
+  assert_throws(code, func, message) {
+    assert.throws(func, message);
   },
 
-  assert_throws_js(code, func) {
-    assert.throws(func);
+  assert_throws_js(code, func, message) {
+    assert.throws(func, message);
   },
 
   assert_unreached() {