diff --git a/packages/compiler-cli/src/ngtsc/file_system/src/invalid_file_system.ts b/packages/compiler-cli/src/ngtsc/file_system/src/invalid_file_system.ts
index b55223efa8cad..5dadaa1fbdb4b 100644
--- a/packages/compiler-cli/src/ngtsc/file_system/src/invalid_file_system.ts
+++ b/packages/compiler-cli/src/ngtsc/file_system/src/invalid_file_system.ts
@@ -22,10 +22,10 @@ export class InvalidFileSystem implements FileSystem {
   readFile(path: AbsoluteFsPath): string {
     throw makeError();
   }
-  readFileBuffer(path: AbsoluteFsPath): Buffer {
+  readFileBuffer(path: AbsoluteFsPath): Uint8Array {
     throw makeError();
   }
-  writeFile(path: AbsoluteFsPath, data: string|Buffer, exclusive?: boolean): void {
+  writeFile(path: AbsoluteFsPath, data: string|Uint8Array, exclusive?: boolean): void {
     throw makeError();
   }
   removeFile(path: AbsoluteFsPath): void {
diff --git a/packages/compiler-cli/src/ngtsc/file_system/src/node_js_file_system.ts b/packages/compiler-cli/src/ngtsc/file_system/src/node_js_file_system.ts
index 44ad46a16dd5f..444092831978d 100644
--- a/packages/compiler-cli/src/ngtsc/file_system/src/node_js_file_system.ts
+++ b/packages/compiler-cli/src/ngtsc/file_system/src/node_js_file_system.ts
@@ -23,10 +23,10 @@ export class NodeJSFileSystem implements FileSystem {
   readFile(path: AbsoluteFsPath): string {
     return fs.readFileSync(path, 'utf8');
   }
-  readFileBuffer(path: AbsoluteFsPath): Buffer {
+  readFileBuffer(path: AbsoluteFsPath): Uint8Array {
     return fs.readFileSync(path);
   }
-  writeFile(path: AbsoluteFsPath, data: string|Buffer, exclusive: boolean = false): void {
+  writeFile(path: AbsoluteFsPath, data: string|Uint8Array, exclusive: boolean = false): void {
     fs.writeFileSync(path, data, exclusive ? {flag: 'wx'} : undefined);
   }
   removeFile(path: AbsoluteFsPath): void {
diff --git a/packages/compiler-cli/src/ngtsc/file_system/src/types.ts b/packages/compiler-cli/src/ngtsc/file_system/src/types.ts
index b232db828c832..bdc660e3011f4 100644
--- a/packages/compiler-cli/src/ngtsc/file_system/src/types.ts
+++ b/packages/compiler-cli/src/ngtsc/file_system/src/types.ts
@@ -37,8 +37,8 @@ export type PathSegment = BrandedPath<'PathSegment'>;
 export interface FileSystem {
   exists(path: AbsoluteFsPath): boolean;
   readFile(path: AbsoluteFsPath): string;
-  readFileBuffer(path: AbsoluteFsPath): Buffer;
-  writeFile(path: AbsoluteFsPath, data: string|Buffer, exclusive?: boolean): void;
+  readFileBuffer(path: AbsoluteFsPath): Uint8Array;
+  writeFile(path: AbsoluteFsPath, data: string|Uint8Array, exclusive?: boolean): void;
   removeFile(path: AbsoluteFsPath): void;
   symlink(target: AbsoluteFsPath, path: AbsoluteFsPath): void;
   readdir(path: AbsoluteFsPath): PathSegment[];
diff --git a/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts b/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts
index 5d4cc337bac56..9122f531eb8e8 100644
--- a/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts
+++ b/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts
@@ -38,16 +38,16 @@ export abstract class MockFileSystem implements FileSystem {
     }
   }
 
-  readFileBuffer(path: AbsoluteFsPath): Buffer {
+  readFileBuffer(path: AbsoluteFsPath): Uint8Array {
     const {entity} = this.findFromPath(path);
     if (isFile(entity)) {
-      return Buffer.isBuffer(entity) ? entity : new Buffer(entity);
+      return entity instanceof Uint8Array ? entity : new Buffer(entity);
     } else {
       throw new MockFileSystemError('ENOENT', path, `File "${path}" does not exist.`);
     }
   }
 
-  writeFile(path: AbsoluteFsPath, data: string|Buffer, exclusive: boolean = false): void {
+  writeFile(path: AbsoluteFsPath, data: string|Uint8Array, exclusive: boolean = false): void {
     const [folderPath, basename] = this.splitIntoFolderAndFile(path);
     const {entity} = this.findFromPath(folderPath);
     if (entity === null || !isFolder(entity)) {
@@ -295,7 +295,7 @@ export type Entity = Folder|File|SymLink;
 export interface Folder {
   [pathSegments: string]: Entity;
 }
-export type File = string|Buffer;
+export type File = string|Uint8Array;
 export class SymLink {
   constructor(public path: AbsoluteFsPath) {}
 }
diff --git a/packages/localize/src/tools/src/translate/asset_files/asset_translation_handler.ts b/packages/localize/src/tools/src/translate/asset_files/asset_translation_handler.ts
index 97ae7ba8a6e2c..3b0ddeec70a08 100644
--- a/packages/localize/src/tools/src/translate/asset_files/asset_translation_handler.ts
+++ b/packages/localize/src/tools/src/translate/asset_files/asset_translation_handler.ts
@@ -17,14 +17,14 @@ import {TranslationBundle, TranslationHandler} from '../translator';
 export class AssetTranslationHandler implements TranslationHandler {
   constructor(private fs: FileSystem) {}
 
-  canTranslate(_relativeFilePath: PathSegment|AbsoluteFsPath, _contents: Buffer): boolean {
+  canTranslate(_relativeFilePath: PathSegment|AbsoluteFsPath, _contents: Uint8Array): boolean {
     return true;
   }
 
   translate(
       diagnostics: Diagnostics, _sourceRoot: AbsoluteFsPath,
-      relativeFilePath: PathSegment|AbsoluteFsPath, contents: Buffer, outputPathFn: OutputPathFn,
-      translations: TranslationBundle[], sourceLocale?: string): void {
+      relativeFilePath: PathSegment|AbsoluteFsPath, contents: Uint8Array,
+      outputPathFn: OutputPathFn, translations: TranslationBundle[], sourceLocale?: string): void {
     for (const translation of translations) {
       this.writeAssetFile(
           diagnostics, outputPathFn, translation.locale, relativeFilePath, contents);
@@ -36,7 +36,7 @@ export class AssetTranslationHandler implements TranslationHandler {
 
   private writeAssetFile(
       diagnostics: Diagnostics, outputPathFn: OutputPathFn, locale: string,
-      relativeFilePath: PathSegment|AbsoluteFsPath, contents: Buffer): void {
+      relativeFilePath: PathSegment|AbsoluteFsPath, contents: Uint8Array): void {
     try {
       const outputPath = absoluteFrom(outputPathFn(locale, relativeFilePath));
       this.fs.ensureDir(this.fs.dirname(outputPath));
diff --git a/packages/localize/src/tools/src/translate/source_files/source_file_translation_handler.ts b/packages/localize/src/tools/src/translate/source_files/source_file_translation_handler.ts
index 4d1e6cc763fb3..18f41636b4dcc 100644
--- a/packages/localize/src/tools/src/translate/source_files/source_file_translation_handler.ts
+++ b/packages/localize/src/tools/src/translate/source_files/source_file_translation_handler.ts
@@ -27,15 +27,15 @@ export class SourceFileTranslationHandler implements TranslationHandler {
       TranslatePluginOptions = {...this.translationOptions, missingTranslation: 'ignore'};
   constructor(private fs: FileSystem, private translationOptions: TranslatePluginOptions = {}) {}
 
-  canTranslate(relativeFilePath: PathSegment|AbsoluteFsPath, _contents: Buffer): boolean {
+  canTranslate(relativeFilePath: PathSegment|AbsoluteFsPath, _contents: Uint8Array): boolean {
     return this.fs.extname(relativeFilePath) === '.js';
   }
 
   translate(
       diagnostics: Diagnostics, sourceRoot: AbsoluteFsPath, relativeFilePath: PathSegment,
-      contents: Buffer, outputPathFn: OutputPathFn, translations: TranslationBundle[],
+      contents: Uint8Array, outputPathFn: OutputPathFn, translations: TranslationBundle[],
       sourceLocale?: string): void {
-    const sourceCode = contents.toString('utf8');
+    const sourceCode = Buffer.from(contents).toString('utf8');
     // A short-circuit check to avoid parsing the file into an AST if it does not contain any
     // `$localize` identifiers.
     if (!sourceCode.includes('$localize')) {
@@ -97,7 +97,7 @@ export class SourceFileTranslationHandler implements TranslationHandler {
 
   private writeSourceFile(
       diagnostics: Diagnostics, outputPathFn: OutputPathFn, locale: string,
-      relativeFilePath: PathSegment, contents: string|Buffer): void {
+      relativeFilePath: PathSegment, contents: string|Uint8Array): void {
     try {
       const outputPath = absoluteFrom(outputPathFn(locale, relativeFilePath));
       this.fs.ensureDir(this.fs.dirname(outputPath));
diff --git a/packages/localize/src/tools/src/translate/translator.ts b/packages/localize/src/tools/src/translate/translator.ts
index a72e1d87bbc5c..6c1d1eb3d6107 100644
--- a/packages/localize/src/tools/src/translate/translator.ts
+++ b/packages/localize/src/tools/src/translate/translator.ts
@@ -35,7 +35,7 @@ export interface TranslationHandler {
    * @param relativeFilePath A relative path from the sourceRoot to the resource file to handle.
    * @param contents The contents of the file to handle.
    */
-  canTranslate(relativeFilePath: PathSegment|AbsoluteFsPath, contents: Buffer): boolean;
+  canTranslate(relativeFilePath: PathSegment|AbsoluteFsPath, contents: Uint8Array): boolean;
 
   /**
    * Translate the file at `relativeFilePath` containing `contents`, using the given `translations`,
@@ -54,8 +54,8 @@ export interface TranslationHandler {
    */
   translate(
       diagnostics: Diagnostics, sourceRoot: AbsoluteFsPath,
-      relativeFilePath: PathSegment|AbsoluteFsPath, contents: Buffer, outputPathFn: OutputPathFn,
-      translations: TranslationBundle[], sourceLocale?: string): void;
+      relativeFilePath: PathSegment|AbsoluteFsPath, contents: Uint8Array,
+      outputPathFn: OutputPathFn, translations: TranslationBundle[], sourceLocale?: string): void;
 }
 
 /**
diff --git a/packages/localize/src/tools/test/translate/translator_spec.ts b/packages/localize/src/tools/test/translate/translator_spec.ts
index 0d2353a1658d6..ea42c7e515480 100644
--- a/packages/localize/src/tools/test/translate/translator_spec.ts
+++ b/packages/localize/src/tools/test/translate/translator_spec.ts
@@ -109,13 +109,13 @@ runInEachFileSystem(() => {
     log: string[] = [];
     constructor(private _canTranslate: boolean = true) {}
 
-    canTranslate(relativePath: string, contents: Buffer) {
-      this.log.push(`canTranslate(${relativePath}, ${contents.toString('utf8')})`);
+    canTranslate(relativePath: string, contents: Uint8Array) {
+      this.log.push(`canTranslate(${relativePath}, ${contents})`);
       return this._canTranslate;
     }
 
     translate(
-        _diagnostics: Diagnostics, rootPath: string, relativePath: string, contents: Buffer,
+        _diagnostics: Diagnostics, rootPath: string, relativePath: string, contents: Uint8Array,
         _outputPathFn: OutputPathFn, _translations: TranslationBundle[], sourceLocale?: string) {
       this.log.push(
           `translate(${rootPath}, ${relativePath}, ${contents}, ...` +