fix: replace indexOf with typedArrayIndexOf for IE11 support (#417)

Author: gesinger

lib/m2ts/metadata-stream.js

@@ -12,6 +12,7 @@
 var
   Stream = require('../utils/stream'),
   StreamTypes = require('./stream-types'),
+  typedArrayIndexOf = require('../utils/typed-array').typedArrayIndexOf,
   // Frames that allow different types of text encoding contain a text
   // encoding description byte [ID3v2.4.0 section 4.]
   textEncodingDescriptionByte = {
@@ -59,7 +60,7 @@ var
       }
 
       // parsing fields [ID3v2.4.0 section 4.14.]
-      mimeTypeEndIndex = frame.data.indexOf(0, i);
+      mimeTypeEndIndex = typedArrayIndexOf(frame.data, 0, i);
       if (mimeTypeEndIndex < 0) {
         // malformed frame
         return;
@@ -73,7 +74,7 @@ var
       frame.pictureType = frame.data[i];
       i++
 
-      descriptionEndIndex = frame.data.indexOf(0, i);
+      descriptionEndIndex = typedArrayIndexOf(frame.data, 0, i);
       if (descriptionEndIndex < 0) {
         // malformed frame
         return;
@@ -104,22 +105,29 @@ var
       frame.values = frame.value.split('\0');
     },
     'TXXX': function(frame) {
-      var i;
+      var descriptionEndIndex;
+
       if (frame.data[0] !== textEncodingDescriptionByte.Utf8) {
         // ignore frames with unrecognized character encodings
         return;
       }
 
-      for (i = 1; i < frame.data.length; i++) {
-        if (frame.data[i] === 0) {
-          // parse the text fields
-          frame.description = parseUtf8(frame.data, 1, i);
-          // do not include the null terminator in the tag value
-          // frames that allow different types of encoding contain terminated text [ID3v2.4.0 section 4.]
-          frame.value = parseUtf8(frame.data, i + 1, frame.data.length).replace(/\0*$/, '');
-          break;
-        }
+      descriptionEndIndex = typedArrayIndexOf(frame.data, 0, 1);
+
+      if (descriptionEndIndex === -1) {
+        return;
       }
+
+      // parse the text fields
+      frame.description = parseUtf8(frame.data, 1, descriptionEndIndex);
+      // do not include the null terminator in the tag value
+      // frames that allow different types of encoding contain terminated text
+      // [ID3v2.4.0 section 4.]
+      frame.value = parseUtf8(
+        frame.data,
+        descriptionEndIndex + 1,
+        frame.data.length
+      ).replace(/\0*$/, '');
       frame.data = frame.value;
     },
     'W*': function(frame) {
@@ -128,22 +136,29 @@ var
       frame.url = parseIso88591(frame.data, 0, frame.data.length).replace(/\0.*$/, '');
     },
     'WXXX': function(frame) {
-      var i;
+      var descriptionEndIndex;
+
       if (frame.data[0] !== textEncodingDescriptionByte.Utf8) {
         // ignore frames with unrecognized character encodings
         return;
       }
 
-      for (i = 1; i < frame.data.length; i++) {
-        if (frame.data[i] === 0) {
-          // parse the description and URL fields
-          frame.description = parseUtf8(frame.data, 1, i);
-          // URL fields are always represented as ISO-8859-1 [ID3v2.4.0 section 4.]
-          // if the value is followed by a string termination all the following information should be ignored [ID3v2.4.0 section 4.3]
-          frame.url = parseIso88591(frame.data, i + 1, frame.data.length).replace(/\0.*$/, '');
-          break;
-        }
+      descriptionEndIndex = typedArrayIndexOf(frame.data, 0, 1);
+
+      if (descriptionEndIndex === -1) {
+        return;
       }
+
+      // parse the description and URL fields
+      frame.description = parseUtf8(frame.data, 1, descriptionEndIndex);
+      // URL fields are always represented as ISO-8859-1 [ID3v2.4.0 section 4.]
+      // if the value is followed by a string termination all the following information
+      // should be ignored [ID3v2.4.0 section 4.3]
+      frame.url = parseIso88591(
+        frame.data,
+        descriptionEndIndex + 1,
+        frame.data.length
+      ).replace(/\0.*$/, '');
     },
     'PRIV': function(frame) {
       var i;

lib/utils/typed-array.js

@@ -0,0 +1,19 @@
+// IE11 doesn't support indexOf for TypedArrays.
+// Once IE11 support is dropped, this function should be removed.
+var typedArrayIndexOf = (typedArray, element, fromIndex) => {
+  if (!typedArray) {
+    return -1;
+  }
+
+  var currentIndex = fromIndex;
+
+  for (; currentIndex < typedArray.length; currentIndex++) {
+    if (typedArray[currentIndex] === element) {
+      return currentIndex;
+    }
+  }
+
+  return -1;
+};
+
+module.exports = { typedArrayIndexOf };

test/utils.typed-array.test.js

@@ -0,0 +1,28 @@
+
+'use strict';
+
+var
+  QUnit = require('qunit'),
+  typedArrayIndexOf = require('../lib/utils/typed-array').typedArrayIndexOf;
+
+QUnit.module('typedArrayIndexOf');
+
+QUnit.test('returns -1 when no typed array', function(assert) {
+  assert.equal(typedArrayIndexOf(null, 5, 0), -1, 'returned -1');
+});
+
+QUnit.test('returns -1 when element not found', function(assert) {
+  assert.equal(typedArrayIndexOf(new Uint8Array([2, 3]), 5, 0), -1, 'returned -1');
+});
+
+QUnit.test('returns -1 when element not found starting from index', function(assert) {
+  assert.equal(typedArrayIndexOf(new Uint8Array([3, 5, 6, 7]), 5, 2), -1, 'returned -1');
+});
+
+QUnit.test('returns index when element found', function(assert) {
+  assert.equal(typedArrayIndexOf(new Uint8Array([2, 3, 5]), 5, 0), 2, 'returned 2');
+});
+
+QUnit.test('returns index when element found starting from index', function(assert) {
+  assert.equal(typedArrayIndexOf(new Uint8Array([2, 3, 5]), 5, 2), 2, 'returned 2');
+});