diff --git a/build/conformance.textproto b/build/conformance.textproto
index c9c59f4e2d..bcbf158ecb 100644
--- a/build/conformance.textproto
+++ b/build/conformance.textproto
@@ -320,3 +320,16 @@ requirement: {
     "instead."
   whitelist_regexp: "lib/net/http_fetch_plugin.js"
 }
+
+# Disallow the use of generators, which are a major performance issue.  See
+# https://github.com/shaka-project/shaka-player/issues/4062#issuecomment-1079428268
+requirement: {
+  type: BANNED_CODE_PATTERN
+  value:
+    "/** @param {*} x */ "
+    "function *template(x) { yield x; }"
+  error_message:
+    "ES6 generators are a major performance issue!  Find another solution. "
+    "See also https://bit.ly/3wAsoj5"
+  whitelist_regexp: "node_modules/"
+}
diff --git a/lib/cea/cea708_service.js b/lib/cea/cea708_service.js
index af8c2615dc..63652c6f48 100644
--- a/lib/cea/cea708_service.js
+++ b/lib/cea/cea708_service.js
@@ -300,17 +300,19 @@ shaka.cea.Cea708Service = class {
   /**
    * Yields each non-null window specified in the 8-bit bitmap.
    * @param {number} bitmap 8 bits corresponding to each of the 8 windows.
-   * @return {!Iterable.<number>}
+   * @return {!Array.<number>}
    * @private
    */
-  * getSpecifiedWindowIds_(bitmap) {
+  getSpecifiedWindowIds_(bitmap) {
+    const ids = [];
     for (let i = 0; i < 8; i++) {
       const windowSpecified = (bitmap & 0x01) === 0x01;
       if (windowSpecified && this.windows_[i]) {
-        yield i;
+        ids.push(i);
       }
       bitmap >>= 1;
     }
+    return ids;
   }
 
   /**
diff --git a/lib/cea/sei_processor.js b/lib/cea/sei_processor.js
index 320264d298..af89c854a5 100644
--- a/lib/cea/sei_processor.js
+++ b/lib/cea/sei_processor.js
@@ -14,9 +14,10 @@ shaka.cea.SeiProcessor = class {
   /**
    * Processes supplemental enhancement information data.
    * @param {!Uint8Array} naluData NALU from which SEI data is to be processed.
-   * @return {!Iterable.<!Uint8Array>}
+   * @return {!Array.<!Uint8Array>}
    */
-  * process(naluData) {
+  process(naluData) {
+    const seiPayloads = [];
     const naluClone = this.removeEmu(naluData);
 
     // The following is an implementation of section 7.3.2.3.1
@@ -41,10 +42,12 @@ shaka.cea.SeiProcessor = class {
       // Payload type 4 is user_data_registered_itu_t_t35, as per the H.264
       // spec. This payload type contains caption data.
       if (payloadType == 0x04) {
-        yield naluClone.subarray(offset, offset + payloadSize);
+        seiPayloads.push(naluClone.subarray(offset, offset + payloadSize));
       }
       offset += payloadSize;
     }
+
+    return seiPayloads;
   }
 
 
diff --git a/lib/dash/segment_list.js b/lib/dash/segment_list.js
index 2814e1f2b5..81dd7fe56f 100644
--- a/lib/dash/segment_list.js
+++ b/lib/dash/segment_list.js
@@ -15,7 +15,6 @@ goog.require('shaka.media.SegmentIndex');
 goog.require('shaka.media.SegmentReference');
 goog.require('shaka.util.Error');
 goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.ManifestParserUtils');
 goog.require('shaka.util.XmlUtils');
 goog.requireType('shaka.dash.DashParser');
@@ -222,7 +221,7 @@ shaka.dash.SegmentList = class {
     /** @type {!Array.<!shaka.media.SegmentReference>} */
     const references = [];
     let prevEndTime = info.startTime;
-    for (const i of shaka.util.Iterables.range(max)) {
+    for (let i = 0; i < max; i++) {
       const segment = info.mediaSegments[i];
       const mediaUri = ManifestParserUtils.resolveUris(
           baseUris, [segment.mediaUri]);
diff --git a/lib/hls/hls_parser.js b/lib/hls/hls_parser.js
index 6b3055239e..236fcae9e3 100644
--- a/lib/hls/hls_parser.js
+++ b/lib/hls/hls_parser.js
@@ -30,7 +30,6 @@ goog.require('shaka.util.CmcdManager');
 goog.require('shaka.util.Error');
 goog.require('shaka.util.FakeEvent');
 goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.LanguageUtils');
 goog.require('shaka.util.ManifestParserUtils');
 goog.require('shaka.util.MimeUtils');
@@ -1869,8 +1868,8 @@ shaka.hls.HlsParser = class {
     // Create SegmentReferences for the partial segments.
     const partialSegmentRefs = [];
     if (this.lowLatencyMode_ && hlsSegment.partialSegments.length) {
-      const enumerate = (it) => shaka.util.Iterables.enumerate(it);
-      for (const {i, item} of enumerate(hlsSegment.partialSegments)) {
+      for (let i = 0; i < hlsSegment.partialSegments.length; i++) {
+        const item = hlsSegment.partialSegments[i];
         const pPreviousReference = i == 0 ?
           previousReference : partialSegmentRefs[partialSegmentRefs.length - 1];
         const pStartTime = (i == 0) ? startTime : pPreviousReference.endTime;
@@ -1891,6 +1890,9 @@ shaka.hls.HlsParser = class {
             this.parseByteRange_(pPreviousReference, pByterange);
         }
         const pUri = item.getAttributeValue('URI');
+        if (!pUri) {
+          continue;
+        }
         const pAbsoluteUri = shaka.hls.Utils.constructAbsoluteUri(
             absoluteMediaPlaylistUri, pUri);
 
@@ -2066,8 +2068,8 @@ shaka.hls.HlsParser = class {
     /** @type {!Array.<!shaka.media.SegmentReference>} */
     const references = [];
 
-    const enumerate = (it) => shaka.util.Iterables.enumerate(it);
-    for (const {i, item} of enumerate(hlsSegments)) {
+    for (let i = 0; i < hlsSegments.length; i++) {
+      const item = hlsSegments[i];
       const previousReference = references[references.length - 1];
       const startTime =
           (i == 0) ? firstStartTime : previousReference.endTime;
diff --git a/lib/hls/manifest_text_parser.js b/lib/hls/manifest_text_parser.js
index a0c9fbb654..15c487716b 100644
--- a/lib/hls/manifest_text_parser.js
+++ b/lib/hls/manifest_text_parser.js
@@ -13,7 +13,6 @@ goog.require('shaka.hls.Segment');
 goog.require('shaka.hls.Tag');
 goog.require('shaka.hls.Utils');
 goog.require('shaka.util.Error');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.StringUtils');
 goog.require('shaka.util.TextParser');
 
@@ -82,8 +81,9 @@ shaka.hls.ManifestTextParser = class {
     const tags = [];
     // Initialize to "true" to skip the first element.
     skip = true;
-    const enumerate = (it) => shaka.util.Iterables.enumerate(it);
-    for (const {i, item: line, next} of enumerate(lines)) {
+    for (let i = 0; i < lines.length; i++) {
+      const line = lines[i];
+      const next = lines[i + 1];
       // Skip comments
       if (shaka.hls.Utils.isComment(line) || skip) {
         skip = false;
diff --git a/lib/media/adaptation_set.js b/lib/media/adaptation_set.js
index 25cda09ccb..b4cf472e1b 100644
--- a/lib/media/adaptation_set.js
+++ b/lib/media/adaptation_set.js
@@ -8,7 +8,6 @@ goog.provide('shaka.media.AdaptationSet');
 
 goog.require('goog.asserts');
 goog.require('shaka.log');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.MimeUtils');
 
 
@@ -215,7 +214,7 @@ shaka.media.AdaptationSet = class {
     codecsA.sort();
     codecsB.sort();
 
-    for (const i of shaka.util.Iterables.range(codecsA.length)) {
+    for (let i = 0; i < codecsA.length; i++) {
       if (codecsA[i] != codecsB[i]) {
         return false;
       }
diff --git a/lib/media/mp4_segment_index_parser.js b/lib/media/mp4_segment_index_parser.js
index e684605045..f231b32bab 100644
--- a/lib/media/mp4_segment_index_parser.js
+++ b/lib/media/mp4_segment_index_parser.js
@@ -11,8 +11,6 @@ goog.require('shaka.log');
 goog.require('shaka.media.InitSegmentReference');
 goog.require('shaka.media.SegmentReference');
 goog.require('shaka.util.Error');
-goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.Mp4Parser');
 
 
@@ -123,8 +121,7 @@ shaka.media.Mp4SegmentIndexParser = class {
     let unscaledStartTime = earliestPresentationTime;
     let startByte = sidxOffset + box.size + firstOffset;
 
-    for (const _ of shaka.util.Iterables.range(referenceCount)) {
-      shaka.util.Functional.ignored(_);
+    for (let i = 0; i < referenceCount; i++) {
       // |chunk| is 1 bit for |referenceType|, and 31 bits for |referenceSize|.
       const chunk = box.reader.readUint32();
       const referenceType = (chunk & 0x80000000) >>> 31;
diff --git a/lib/media/time_ranges_utils.js b/lib/media/time_ranges_utils.js
index db38e4317b..7718389ed0 100644
--- a/lib/media/time_ranges_utils.js
+++ b/lib/media/time_ranges_utils.js
@@ -6,8 +6,6 @@
 
 goog.provide('shaka.media.TimeRangesUtils');
 
-goog.require('shaka.util.Iterables');
-
 
 /**
  * @summary A set of utility functions for dealing with TimeRanges objects.
@@ -157,7 +155,7 @@ shaka.media.TimeRangesUtils = class {
       return [];
     }
     const ret = [];
-    for (const i of shaka.util.Iterables.range(b.length)) {
+    for (let i = 0; i < b.length; i++) {
       ret.push({start: b.start(i), end: b.end(i)});
     }
     return ret;
diff --git a/lib/polyfill/all.js b/lib/polyfill/all.js
index e5ad6bb420..a0337db699 100644
--- a/lib/polyfill/all.js
+++ b/lib/polyfill/all.js
@@ -7,7 +7,6 @@
 goog.provide('shaka.polyfill');
 
 goog.require('shaka.log');
-goog.require('shaka.util.Iterables');
 
 
 /**
@@ -40,8 +39,8 @@ shaka.polyfill = class {
    */
   static register(polyfill, priority) {
     const newItem = {priority: priority || 0, callback: polyfill};
-    const enumerate = (it) => shaka.util.Iterables.enumerate(it);
-    for (const {i, item} of enumerate(shaka.polyfill.polyfills_)) {
+    for (let i = 0; i < shaka.polyfill.polyfills_.length; i++) {
+      const item = shaka.polyfill.polyfills_[i];
       if (item.priority < newItem.priority) {
         shaka.polyfill.polyfills_.splice(i, 0, newItem);
         return;
diff --git a/lib/util/buffer_utils.js b/lib/util/buffer_utils.js
index 141e8dd5c3..36540afb4a 100644
--- a/lib/util/buffer_utils.js
+++ b/lib/util/buffer_utils.js
@@ -6,8 +6,6 @@
 
 goog.provide('shaka.util.BufferUtils');
 
-goog.require('shaka.util.Iterables');
-
 
 /**
  * @summary A set of BufferSource utility functions.
@@ -45,7 +43,7 @@ shaka.util.BufferUtils = class {
 
     const uint8A = shaka.util.BufferUtils.toUint8(arr1);
     const uint8B = shaka.util.BufferUtils.toUint8(arr2);
-    for (const i of shaka.util.Iterables.range(arr1.byteLength)) {
+    for (let i = 0; i < arr1.byteLength; i++) {
       if (uint8A[i] != uint8B[i]) {
         return false;
       }
diff --git a/lib/util/ebml_parser.js b/lib/util/ebml_parser.js
index 5475532259..d9184c64d6 100644
--- a/lib/util/ebml_parser.js
+++ b/lib/util/ebml_parser.js
@@ -11,7 +11,6 @@ goog.require('goog.asserts');
 goog.require('shaka.util.BufferUtils');
 goog.require('shaka.util.DataViewReader');
 goog.require('shaka.util.Error');
-goog.require('shaka.util.Iterables');
 
 
 /**
@@ -157,7 +156,8 @@ shaka.util.EbmlParser = class {
     }
 
     let value = 0;
-    for (const {item, i} of shaka.util.Iterables.enumerate(vint)) {
+    for (let i = 0; i < vint.length; i++) {
+      const item = vint[i];
       if (i == 0) {
         // Mask out the first few bits of |vint|'s first byte to get the most
         // significant bits of |vint|'s value. If |vint| is 8 bytes wide then
@@ -267,7 +267,7 @@ shaka.util.EbmlElement = class {
 
     let value = 0;
 
-    for (const i of shaka.util.Iterables.range(this.dataView_.byteLength)) {
+    for (let i = 0; i < this.dataView_.byteLength; i++) {
       const chunk = this.dataView_.getUint8(i);
       value = (256 * value) + chunk;
     }
diff --git a/lib/util/iterables.js b/lib/util/iterables.js
index 706434dff6..77f2812548 100644
--- a/lib/util/iterables.js
+++ b/lib/util/iterables.js
@@ -75,50 +75,4 @@ shaka.util.Iterables = class {
     }
     return out;
   }
-
-  /**
-   * Returns an iterable that contains numbers in the range [0, end).
-   *
-   * @param {number} end The exclusive end of the list.
-   * @return {!Iterable.<number>}
-   */
-  static* range(end) {
-    for (let i = 0; i < end; i++) {
-      yield i;
-    }
-  }
-
-  /**
-   * Iterates over an iterable object and includes additional info about each
-   * item:
-   * - The zero-based index of the element.
-   * - The next item in the list, if it exists.
-   * - The previous item in the list, if it exists.
-   *
-   * @param {!Iterable.<T>} iterable
-   * @return {!Iterable.<
-   *     {i: number, item: T, prev: (T|undefined), next: (T|undefined)}>}
-   * @template T
-   */
-  static* enumerate(iterable) {
-    // Since we want the "next" item, we need to skip the first item and return
-    // elements one in the past.  So as we iterate, we are getting the "next"
-    // element and yielding the one from the previous iteration.
-    let i = -1;
-    let prev = undefined;
-    let item = undefined;
-    for (const next of iterable) {
-      if (i >= 0) {
-        yield {i, item, prev, next};
-      }
-      i++;
-      prev = item;
-      item = next;
-    }
-    if (i != -1) {
-      // If it's still -1, there were no items.  Otherwise we need to yield
-      // the last item.
-      yield {i, prev, item, next: undefined};
-    }
-  }
 };
diff --git a/lib/util/mp4_box_parsers.js b/lib/util/mp4_box_parsers.js
index 6479ba01f1..a9a6bfac48 100644
--- a/lib/util/mp4_box_parsers.js
+++ b/lib/util/mp4_box_parsers.js
@@ -7,8 +7,6 @@
 goog.provide('shaka.util.Mp4BoxParsers');
 
 goog.require('shaka.util.DataViewReader');
-goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 
 shaka.util.Mp4BoxParsers = class {
   /**
@@ -125,8 +123,7 @@ shaka.util.Mp4BoxParsers = class {
       reader.skip(4);
     }
 
-    for (const _ of shaka.util.Iterables.range(sampleCount)) {
-      shaka.util.Functional.ignored(_);
+    for (let i = 0; i < sampleCount; i++) {
       /** @type {shaka.util.ParsedTRUNSample} */
       const sample = {
         sampleDuration: null,
diff --git a/lib/util/mp4_parser.js b/lib/util/mp4_parser.js
index 8a0475c791..7d0ebf0818 100644
--- a/lib/util/mp4_parser.js
+++ b/lib/util/mp4_parser.js
@@ -9,8 +9,6 @@ goog.provide('shaka.util.Mp4Parser');
 goog.require('goog.asserts');
 goog.require('shaka.log');
 goog.require('shaka.util.DataViewReader');
-goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 
 
 /**
@@ -229,8 +227,7 @@ shaka.util.Mp4Parser = class {
     // start position.  The header size varies.
     const headerSize = shaka.util.Mp4Parser.headerSize(box);
     const count = box.reader.readUint32();
-    for (const _ of shaka.util.Iterables.range(count)) {
-      shaka.util.Functional.ignored(_);
+    for (let i = 0; i < count; i++) {
       box.parser.parseNext(box.start + headerSize, box.reader, box.partialOkay);
       if (box.parser.done_) {
         break;
diff --git a/lib/util/periods.js b/lib/util/periods.js
index ac1a9bee41..9f41b98162 100644
--- a/lib/util/periods.js
+++ b/lib/util/periods.js
@@ -14,7 +14,6 @@ goog.require('shaka.media.SegmentIndex');
 goog.require('shaka.util.ArrayUtils');
 goog.require('shaka.util.Error');
 goog.require('shaka.util.IReleasable');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.LanguageUtils');
 goog.require('shaka.util.ManifestParserUtils');
 goog.require('shaka.util.MapUtils');
@@ -98,7 +97,6 @@ shaka.util.PeriodCombiner = class {
    */
   async combinePeriods(periods, isDynamic) {
     const ContentType = shaka.util.ManifestParserUtils.ContentType;
-    const Iterables = shaka.util.Iterables;
 
     shaka.util.PeriodCombiner.filterOutAudioStreamDuplicates_(periods);
     shaka.util.PeriodCombiner.filterOutVideoStreamDuplicates_(periods);
@@ -118,7 +116,8 @@ shaka.util.PeriodCombiner = class {
       // Find the first period we haven't seen before.  Tag all the periods we
       // see now as "used".
       let firstNewPeriodIndex = -1;
-      for (const {i, item: period} of Iterables.enumerate(periods)) {
+      for (let i = 0; i < periods.length; i++) {
+        const period = periods[i];
         if (this.usedPeriodIds_.has(period.id)) {
           // This isn't new.
         } else {
@@ -511,13 +510,12 @@ shaka.util.PeriodCombiner = class {
   static async combine_(
       outputStreams, streamsPerPeriod, firstNewPeriodIndex, clone, concat) {
     const ContentType = shaka.util.ManifestParserUtils.ContentType;
-    const Iterables = shaka.util.Iterables;
 
     const unusedStreamsPerPeriod = [];
-    for (const {i, item: streams} of Iterables.enumerate(streamsPerPeriod)) {
+    for (let i = 0; i < streamsPerPeriod.length; i++) {
       if (i >= firstNewPeriodIndex) {
         // This periods streams are all new.
-        unusedStreamsPerPeriod.push(new Set(streams));
+        unusedStreamsPerPeriod.push(new Set(streamsPerPeriod[i]));
       } else {
         // This period's streams have all been used already.
         unusedStreamsPerPeriod.push(new Set());
@@ -669,12 +667,12 @@ shaka.util.PeriodCombiner = class {
 
     // Concatenate the new matches onto the stream, starting at the first new
     // period.
-    const Iterables = shaka.util.Iterables;
     // Satisfy the compiler about the type.
     // Also checks if the segmentIndex is still valid after the async
     // operations, to make sure we stop if the active stream has changed.
     if (outputStream.segmentIndex instanceof shaka.media.MetaSegmentIndex) {
-      for (const {i, item: match} of Iterables.enumerate(streams)) {
+      for (let i = 0; i < streams.length; i++) {
+        const match = streams[i];
         if (match.segmentIndex && i >= firstNewPeriodIndex) {
           goog.asserts.assert(match.segmentIndex,
               'stream should have a segmentIndex.');
@@ -769,9 +767,9 @@ shaka.util.PeriodCombiner = class {
 
     // Concatenate the new matches onto the stream, starting at the first new
     // period.
-    const Iterables = shaka.util.Iterables;
-    for (const {i, item: match} of Iterables.enumerate(matches)) {
+    for (let i = 0; i < matches.length; i++) {
       if (i >= firstNewPeriodIndex) {
+        const match = matches[i];
         concat(outputStream, match);
 
         // We only consider an audio stream "used" if its language is related to
diff --git a/lib/util/pssh.js b/lib/util/pssh.js
index e967fa93db..0f829fb09d 100644
--- a/lib/util/pssh.js
+++ b/lib/util/pssh.js
@@ -9,8 +9,6 @@ goog.provide('shaka.util.Pssh');
 goog.require('goog.asserts');
 goog.require('shaka.log');
 goog.require('shaka.util.BufferUtils');
-goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.Mp4Parser');
 goog.require('shaka.util.Uint8ArrayUtils');
 
@@ -83,8 +81,7 @@ shaka.util.Pssh = class {
         shaka.util.Uint8ArrayUtils.toHex(box.reader.readBytes(16)));
     if (box.version > 0) {
       const numKeyIds = box.reader.readUint32();
-      for (const _ of shaka.util.Iterables.range(numKeyIds)) {
-        shaka.util.Functional.ignored(_);
+      for (let i = 0; i < numKeyIds; i++) {
         const keyId =
             shaka.util.Uint8ArrayUtils.toHex(box.reader.readBytes(16));
         this.cencKeyIds.push(keyId);
diff --git a/lib/util/string_utils.js b/lib/util/string_utils.js
index 76f9f834ee..895fd08358 100644
--- a/lib/util/string_utils.js
+++ b/lib/util/string_utils.js
@@ -10,7 +10,6 @@ goog.require('goog.asserts');
 goog.require('shaka.log');
 goog.require('shaka.util.BufferUtils');
 goog.require('shaka.util.Error');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.Lazy');
 
 
@@ -81,7 +80,7 @@ shaka.util.StringUtils = class {
     const length = Math.floor(data.byteLength / 2);
     const arr = new Uint16Array(length);
     const dataView = shaka.util.BufferUtils.toDataView(data);
-    for (const i of shaka.util.Iterables.range(length)) {
+    for (let i = 0; i < length; i++) {
       arr[i] = dataView.getUint16(i * 2, littleEndian);
     }
     return shaka.util.StringUtils.fromCharCode(arr);
diff --git a/lib/util/uint8array_utils.js b/lib/util/uint8array_utils.js
index 0ddcdd1a43..b0b8c02061 100644
--- a/lib/util/uint8array_utils.js
+++ b/lib/util/uint8array_utils.js
@@ -8,7 +8,6 @@ goog.provide('shaka.util.Uint8ArrayUtils');
 
 goog.require('shaka.Deprecate');
 goog.require('shaka.util.BufferUtils');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.StringUtils');
 
 
@@ -90,7 +89,7 @@ shaka.util.Uint8ArrayUtils = class {
   static fromHex(str) {
     const size = str.length / 2;
     const arr = new Uint8Array(size);
-    for (const i of shaka.util.Iterables.range(size)) {
+    for (let i = 0; i < size; i++) {
       arr[i] = window.parseInt(str.substr(i * 2, 2), 16);
     }
     return arr;
diff --git a/test/cast/cast_receiver_integration.js b/test/cast/cast_receiver_integration.js
index f7eeb53b31..d1512e2de8 100644
--- a/test/cast/cast_receiver_integration.js
+++ b/test/cast/cast_receiver_integration.js
@@ -15,8 +15,6 @@ goog.require('shaka.net.NetworkingEngine');
 goog.require('shaka.test.TestScheme');
 goog.require('shaka.test.UiUtils');
 goog.require('shaka.util.EventManager');
-goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.Platform');
 goog.require('shaka.util.PublicPromise');
 
@@ -198,8 +196,7 @@ filterDescribe('CastReceiver', castReceiverIntegrationSupport, () => {
       // the average length is expected to be lower than the length of the first
       // update message.
       let totalLength = 0;
-      for (const _ of shaka.util.Iterables.range(50)) {
-        shaka.util.Functional.ignored(_);
+      for (let i = 0; i < 50; i++) {
         // eslint-disable-next-line no-await-in-loop
         const message = await waitForUpdateMessage();
         totalLength += message.length;
diff --git a/test/dash/dash_parser_content_protection_unit.js b/test/dash/dash_parser_content_protection_unit.js
index 093512f74b..8e004ef267 100644
--- a/test/dash/dash_parser_content_protection_unit.js
+++ b/test/dash/dash_parser_content_protection_unit.js
@@ -9,7 +9,6 @@ goog.require('shaka.dash.DashParser');
 goog.require('shaka.test.Dash');
 goog.require('shaka.test.FakeNetworkingEngine');
 goog.require('shaka.util.Error');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.PlayerConfiguration');
 goog.require('shaka.util.Uint8ArrayUtils');
 
@@ -142,7 +141,7 @@ describe('DashParser ContentProtection', () => {
 
     const variants = [];
     const numVariants = 2;
-    for (const i of shaka.util.Iterables.range(numVariants)) {
+    for (let i = 0; i < numVariants; i++) {
       const variant = jasmine.objectContaining({
         video: jasmine.objectContaining({
           keyIds: new Set(keyIds[i] ? [keyIds[i]] : []),
diff --git a/test/dash/mpd_utils_unit.js b/test/dash/mpd_utils_unit.js
index 06536294a8..fc00cf1be9 100644
--- a/test/dash/mpd_utils_unit.js
+++ b/test/dash/mpd_utils_unit.js
@@ -9,7 +9,6 @@ goog.require('shaka.net.NetworkingEngine');
 goog.require('shaka.test.FakeNetworkingEngine');
 goog.require('shaka.test.Util');
 goog.require('shaka.util.Error');
-goog.require('shaka.util.Iterables');
 goog.requireType('shaka.util.PublicPromise');
 
 describe('MpdUtils', () => {
@@ -536,7 +535,7 @@ describe('MpdUtils', () => {
           '<ToReplace xlink:href="https://xlink0" xlink:actuate="onLoad" />');
       // Create a large but finite number of links, so this won't
       // infinitely recurse if there isn't a depth limit.
-      for (const i of shaka.util.Iterables.range(20)) {
+      for (let i = 0; i < 20; i++) {
         const key = 'https://xlink' + i;
         const value = makeRecursiveXMLString(0, 'https://xlink' + (i + 1));
 
@@ -659,7 +658,7 @@ describe('MpdUtils', () => {
           '<ToReplace xlink:href="https://xlink0" xlink:actuate="onLoad" />');
       // Create a few links.  This is few enough that it would succeed if we
       // didn't abort it.
-      for (const i of shaka.util.Iterables.range(4)) {
+      for (let i = 0; i < 4; i++) {
         const key = 'https://xlink' + i;
         const value = makeRecursiveXMLString(0, 'https://xlink' + (i + 1));
 
diff --git a/test/hls/hls_live_unit.js b/test/hls/hls_live_unit.js
index a9ee408d66..97e80a406a 100644
--- a/test/hls/hls_live_unit.js
+++ b/test/hls/hls_live_unit.js
@@ -9,8 +9,6 @@ goog.require('shaka.net.NetworkingEngine');
 goog.require('shaka.test.FakeNetworkingEngine');
 goog.require('shaka.test.ManifestParser');
 goog.require('shaka.test.Util');
-goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.PlayerConfiguration');
 goog.require('shaka.util.Uint8ArrayUtils');
 goog.requireType('shaka.util.PublicPromise');
@@ -394,8 +392,8 @@ describe('HlsParser live', () => {
       '#EXT-X-MAP:URI="init.mp4",BYTERANGE="616@0"\n',
       '#EXT-X-MEDIA-SEQUENCE:0\n',
     ].join('');
-    for (const _ of shaka.util.Iterables.range(1000)) {
-      shaka.util.Functional.ignored(_);
+
+    for (let i = 0; i < 1000; i++) {
       mediaWithManySegments += '#EXTINF:2,\n';
       mediaWithManySegments += 'main.mp4\n';
     }
diff --git a/test/media/buffering_observer_unit.js b/test/media/buffering_observer_unit.js
index 40188320bb..21f7b37c77 100644
--- a/test/media/buffering_observer_unit.js
+++ b/test/media/buffering_observer_unit.js
@@ -5,7 +5,6 @@
  */
 
 goog.require('shaka.media.BufferingObserver');
-goog.require('shaka.util.Iterables');
 
 describe('BufferingObserver', () => {
   const BufferingObserver = shaka.media.BufferingObserver;
@@ -115,7 +114,7 @@ describe('BufferingObserver', () => {
       /** @type {boolean} */
       let changed;
 
-      for (const lead of shaka.util.Iterables.range(5)) {
+      for (let lead = 0; lead < 5; lead++) {
         changed = controller.update(lead, /* toEnd= */ false);
         expect(changed).toBeFalsy();
       }
diff --git a/test/media/streaming_engine_unit.js b/test/media/streaming_engine_unit.js
index 713f765bab..55e7dac165 100644
--- a/test/media/streaming_engine_unit.js
+++ b/test/media/streaming_engine_unit.js
@@ -18,7 +18,6 @@ goog.require('shaka.test.StreamingEngineUtil');
 goog.require('shaka.test.Util');
 goog.require('shaka.util.AbortableOperation');
 goog.require('shaka.util.Error');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.ManifestParserUtils');
 goog.require('shaka.util.MimeUtils');
 goog.require('shaka.util.PlayerConfiguration');
@@ -284,7 +283,7 @@ describe('StreamingEngine', () => {
     };
 
     const segmentsInFirstPeriod = 12;
-    for (const i of shaka.util.Iterables.range(segmentsInFirstPeriod)) {
+    for (let i = 0; i < segmentsInFirstPeriod; i++) {
       segmentData[ContentType.AUDIO].segments.push(
           makeBuffer(segmentSizes[ContentType.AUDIO]));
       segmentData[ContentType.VIDEO].segments.push(
@@ -298,7 +297,7 @@ describe('StreamingEngine', () => {
     }
 
     const segmentsInSecondPeriod = 2;
-    for (const i of shaka.util.Iterables.range(segmentsInSecondPeriod)) {
+    for (let i = 0; i < segmentsInSecondPeriod; i++) {
       segmentData[ContentType.AUDIO].segments.push(
           makeBuffer(segmentSizes[ContentType.AUDIO]));
       segmentData[ContentType.VIDEO].segments.push(
@@ -652,7 +651,7 @@ describe('StreamingEngine', () => {
     // should be buffered.  Those segment numbers are 1-based, and this array
     // is 0-based, so we expect i >= 9 to be downloaded.
     const segments = mediaSourceEngine.segments;
-    for (const i of shaka.util.Iterables.range(14)) {
+    for (let i = 0; i < 14; i++) {
       expect(segments[ContentType.AUDIO][i]).withContext(i).toBe(i >= 9);
       expect(segments[ContentType.VIDEO][i]).withContext(i).toBe(i >= 9);
       expect(segments[ContentType.TEXT][i]).withContext(i).toBe(i >= 9);
@@ -1801,7 +1800,7 @@ describe('StreamingEngine', () => {
 
       // Since we performed an unbuffered seek into the second Period, the
       // first 12 segments should not be buffered.
-      for (const i of shaka.util.Iterables.range(14)) {
+      for (let i = 0; i < 14; i++) {
         expect(mediaSourceEngine.segments[ContentType.AUDIO][i]).toBe(i >= 12);
         expect(mediaSourceEngine.segments[ContentType.VIDEO][i]).toBe(i >= 12);
         expect(mediaSourceEngine.segments[ContentType.TEXT][i]).toBe(i >= 12);
@@ -2603,7 +2602,7 @@ describe('StreamingEngine', () => {
       // should be buffered.  Those segment numbers are 1-based, and this array
       // is 0-based, so we expect i >= 9 to be downloaded.
       const segments = mediaSourceEngine.segments;
-      for (const i of shaka.util.Iterables.range(14)) {
+      for (let i = 0; i < 14; i++) {
         expect(segments[ContentType.AUDIO][i]).withContext(i).toBe(i >= 9);
         expect(segments[ContentType.VIDEO][i]).withContext(i).toBe(i >= 9);
         expect(segments[ContentType.TEXT][i]).withContext(i).toBe(i >= 9);
diff --git a/test/player_integration.js b/test/player_integration.js
index 33254fd77b..fa9bba8939 100644
--- a/test/player_integration.js
+++ b/test/player_integration.js
@@ -17,8 +17,6 @@ goog.require('shaka.test.UiUtils');
 goog.require('shaka.test.Util');
 goog.require('shaka.test.Waiter');
 goog.require('shaka.util.EventManager');
-goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 
 describe('Player', () => {
   /** @type {!jasmine.Spy} */
@@ -931,8 +929,7 @@ describe('Player', () => {
     }
 
     async function waitUntilBuffered(amount) {
-      for (const _ of shaka.util.Iterables.range(25)) {
-        shaka.util.Functional.ignored(_);
+      for (let i = 0; i < 25; i++) {
         // We buffer from an internal segment, so this shouldn't take long to
         // buffer.
         await Util.delay(0.1);  // eslint-disable-line no-await-in-loop
diff --git a/test/player_unit.js b/test/player_unit.js
index 2375e010db..805b47e7fc 100644
--- a/test/player_unit.js
+++ b/test/player_unit.js
@@ -24,7 +24,6 @@ goog.require('shaka.test.ManifestGenerator');
 goog.require('shaka.test.Util');
 goog.require('shaka.util.ConfigUtils');
 goog.require('shaka.util.Error');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.ManifestParserUtils');
 goog.requireType('shaka.media.Playhead');
 
@@ -2177,8 +2176,8 @@ describe('Player', () => {
     async function runTest(languages, preference, expectedIndex) {
       // A manifest we can use to test language selection.
       manifest = shaka.test.ManifestGenerator.generate((manifest) => {
-        const enumerate = (it) => shaka.util.Iterables.enumerate(it);
-        for (const {i, item: lang} of enumerate(languages)) {
+        for (let i = 0; i < languages.length; i++) {
+          const lang = languages[i];
           if (lang.charAt(0) == '*') {
             manifest.addVariant(i, (variant) => {
               variant.primary = true;
diff --git a/test/test/util/indexeddb_utils.js b/test/test/util/indexeddb_utils.js
index 33d5fdd909..b2d60c498e 100644
--- a/test/test/util/indexeddb_utils.js
+++ b/test/test/util/indexeddb_utils.js
@@ -7,8 +7,6 @@
 goog.provide('shaka.test.IndexedDBUtils');
 
 goog.require('shaka.test.Util');
-goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.PublicPromise');
 
 
@@ -41,8 +39,7 @@ shaka.test.IndexedDBUtils = class {
     // connection after 5 attempts (with delays in between), just give
     // up.
     let lastError;
-    for (const _ of shaka.util.Iterables.range(5)) {
-      shaka.util.Functional.ignored(_);
+    for (let i = 0; i < 5; i++) {
       try {
         return await tryOpen();  // eslint-disable-line no-await-in-loop
       } catch (e) {  // eslint-disable-line no-restricted-syntax
diff --git a/test/test/util/manifest_generator.js b/test/test/util/manifest_generator.js
index 4906842ac4..f505786dcb 100644
--- a/test/test/util/manifest_generator.js
+++ b/test/test/util/manifest_generator.js
@@ -8,7 +8,6 @@ goog.provide('shaka.test.ManifestGenerator');
 
 goog.require('goog.asserts');
 goog.require('shaka.test.Util');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.ManifestParserUtils');
 goog.require('shaka.util.Uint8ArrayUtils');
 goog.requireType('shaka.media.InitSegmentReference');
@@ -621,7 +620,7 @@ shaka.test.ManifestGenerator.Stream = class {
     const segmentCount = totalDuration / segmentDuration;
     const references = [];
 
-    for (const index of shaka.util.Iterables.range(segmentCount)) {
+    for (let index = 0; index < segmentCount; index++) {
       const getUris = () => [sprintf(template, index)];
       const start = index * segmentDuration;
       const end = Math.min(totalDuration, (index + 1) * segmentDuration);
diff --git a/test/test/util/util.js b/test/test/util/util.js
index 1586d1303c..47c4c5876b 100644
--- a/test/test/util/util.js
+++ b/test/test/util/util.js
@@ -10,8 +10,6 @@ goog.provide('shaka.test.Util');
 goog.require('goog.asserts');
 goog.require('shaka.media.InitSegmentReference');
 goog.require('shaka.media.SegmentReference');
-goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
 goog.require('shaka.util.StringUtils');
 goog.require('shaka.util.XmlUtils');
 goog.requireType('shaka.util.Error');
@@ -52,10 +50,9 @@ shaka.test.Util = class {
    */
   static async fakeEventLoop(duration, onTick) {
     // Run this synchronously:
-    for (const time of shaka.util.Iterables.range(duration)) {
+    for (let time = 0; time < duration; time++) {
       // We shouldn't need more than 6 rounds.
-      for (const _ of shaka.util.Iterables.range(6)) {
-        shaka.util.Functional.ignored(_);
+      for (let i = 0; i < 6; i++) {
         jasmine.clock().tick(0);
         await Promise.resolve();  // eslint-disable-line no-await-in-loop
       }
@@ -203,7 +200,7 @@ shaka.test.Util = class {
       if (actual.childNodes.length != expected.childNodes.length) {
         return prospectiveDiff + 'Different child node list length.';
       }
-      for (const i of shaka.util.Iterables.range(actual.childNodes.length)) {
+      for (let i = 0; i < actual.childNodes.length; i++) {
         const aNode = actual.childNodes[i];
         const eNode = expected.childNodes[i];
         const diff =
diff --git a/test/ui/ui_unit.js b/test/ui/ui_unit.js
index d05de14c13..1bf150f06e 100644
--- a/test/ui/ui_unit.js
+++ b/test/ui/ui_unit.js
@@ -12,8 +12,7 @@ goog.require('shaka.test.UiUtils');
 goog.require('shaka.test.Util');
 goog.require('shaka.ui.OverflowMenu');
 goog.require('shaka.ui.ResolutionSelection');
-goog.require('shaka.util.Functional');
-goog.require('shaka.util.Iterables');
+goog.require('shaka.util.Platform');
 goog.require('shaka.util.Platform');
 goog.requireType('shaka.Player');
 goog.requireType('shaka.ui.Controls');
@@ -137,8 +136,7 @@ describe('UI', () => {
         // Four is just a random number I (ismena) came up with to test a
         // multi-video use case. It could be replaces with any other
         // (reasonable) number.
-        for (const _ of shaka.util.Iterables.range(4)) {
-          shaka.util.Functional.ignored(_);
+        for (let i = 0; i < 4; i++) {
           const video = /** @type {!HTMLVideoElement} */
               (document.createElement('video'));
 
diff --git a/test/util/iterables_unit.js b/test/util/iterables_unit.js
index b4096cbced..5907f5a747 100644
--- a/test/util/iterables_unit.js
+++ b/test/util/iterables_unit.js
@@ -67,66 +67,4 @@ describe('Iterables', () => {
       expect(Iterables.filter(input, (x) => x < 0)).toEqual([]);
     });
   });
-
-  describe('enumerate', () => {
-    function enumerate(it) {
-      return Array.from(Iterables.enumerate(it));
-    }
-
-    it('works with no items', () => {
-      expect(enumerate([])).toEqual([]);
-    });
-
-    it('works with one item', () => {
-      expect(enumerate([999]))
-          .toEqual([{i: 0, item: 999, prev: undefined, next: undefined}]);
-    });
-
-    it('works with special values', () => {
-      expect(enumerate([[]]))
-          .toEqual([{i: 0, item: [], prev: undefined, next: undefined}]);
-      expect(enumerate([0]))
-          .toEqual([{i: 0, item: 0, prev: undefined, next: undefined}]);
-      expect(enumerate([null]))
-          .toEqual([{i: 0, item: null, prev: undefined, next: undefined}]);
-      expect(enumerate([undefined]))
-          .toEqual([{i: 0, item: undefined, prev: undefined, next: undefined}]);
-    });
-
-    it('works with two items', () => {
-      expect(enumerate([888, 999]))
-          .toEqual([
-            {i: 0, item: 888, prev: undefined, next: 999},
-            {i: 1, item: 999, prev: 888, next: undefined},
-          ]);
-    });
-
-    it('works with three items', () => {
-      expect(enumerate([777, 888, 999]))
-          .toEqual([
-            {i: 0, item: 777, prev: undefined, next: 888},
-            {i: 1, item: 888, prev: 777, next: 999},
-            {i: 2, item: 999, prev: 888, next: undefined},
-          ]);
-    });
-
-    it('keeps references', () => {
-      const expected = [
-        {a: 'x'},
-        {b: 'y'},
-        {c: 'z'},
-      ];
-      const actual = enumerate(expected);
-
-      expect(actual[0].item).toBe(expected[0]);
-      expect(actual[0].next).toBe(expected[1]);
-
-      expect(actual[1].prev).toBe(expected[0]);
-      expect(actual[1].item).toBe(expected[1]);
-      expect(actual[1].next).toBe(expected[2]);
-
-      expect(actual[2].prev).toBe(expected[1]);
-      expect(actual[2].item).toBe(expected[2]);
-    });
-  });
 });