diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index 9693d6b4c33..669cbcbcf0c 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -143,7 +143,7 @@ namespace ts {
 
                     // create asynchronous output for the importDeclarations
                     if (moduleElementDeclarationEmitInfo.length) {
-                        let oldWriter = writer;
+                        const oldWriter = writer;
                         forEach(moduleElementDeclarationEmitInfo, aliasEmitInfo => {
                             if (aliasEmitInfo.isVisible && !aliasEmitInfo.asynchronousOutput) {
                                 Debug.assert(aliasEmitInfo.node.kind === SyntaxKind.ImportDeclaration);
@@ -744,7 +744,7 @@ namespace ts {
 
         function emitExternalModuleSpecifier(moduleSpecifier: Expression) {
             if (moduleSpecifier.kind === SyntaxKind.StringLiteral && (!root) && (compilerOptions.out || compilerOptions.outFile)) {
-                let moduleName = getExternalModuleNameFromDeclaration(host, resolver, moduleSpecifier.parent as (ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration));
+                const moduleName = getExternalModuleNameFromDeclaration(host, resolver, moduleSpecifier.parent as (ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration));
                 if (moduleName) {
                     write("\"");
                     write(moduleName);
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 8635dc44f91..ce92150f9fd 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -12,7 +12,7 @@ namespace ts {
     }
 
     export function getExternalModuleNameFromDeclaration(host: EmitHost, resolver: EmitResolver, declaration: ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration): string {
-        let file = resolver.getExternalModuleFileFromDeclaration(declaration);
+        const file = resolver.getExternalModuleFileFromDeclaration(declaration);
         if (!file || isDeclarationFile(file)) {
             return undefined;
         }
@@ -355,7 +355,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
             else {
                 forEach(host.getSourceFiles(), sourceFile => {
                     if (shouldEmitToOwnFile(sourceFile, compilerOptions)) {
-                        let jsFilePath = getOwnEmitOutputFilePath(sourceFile, host, shouldEmitJsx(sourceFile) ? ".jsx" : ".js");
+                        const jsFilePath = getOwnEmitOutputFilePath(sourceFile, host, shouldEmitJsx(sourceFile) ? ".jsx" : ".js");
                         emitFile(jsFilePath, sourceFile);
                     }
                 });
@@ -616,7 +616,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                 if (compilerOptions.sourceMap || compilerOptions.inlineSourceMap) {
                     initializeEmitterWithSourceMaps(jsFilePath, root);
                 }
-    
+
                 if (root) {
                     // Do not call emit directly. It does not set the currentSourceFile.
                     emitSourceFile(root);
@@ -7372,7 +7372,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                     }
 
                     if (emitRelativePathAsModuleName) {
-                        let name = getExternalModuleNameFromDeclaration(host, resolver, externalImports[i]);
+                        const name = getExternalModuleNameFromDeclaration(host, resolver, externalImports[i]);
                         if (name) {
                             text = `"${name}"`;
                         }
@@ -7422,7 +7422,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                     let externalModuleName = getExternalModuleNameText(importNode);
 
                     if (emitRelativePathAsModuleName) {
-                        let name = getExternalModuleNameFromDeclaration(host, resolver, importNode);
+                        const name = getExternalModuleNameFromDeclaration(host, resolver, importNode);
                         if (name) {
                             externalModuleName = `"${name}"`;
                         }
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index a9aadec16b3..17d780df574 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -1805,8 +1805,8 @@ namespace ts {
      * Resolves a local path to a path which is absolute to the base of the emit
      */
     export function getExternalModuleNameFromPath(host: EmitHost, fileName: string): string {
-        let dir = host.getCurrentDirectory();
-        let relativePath = getRelativePathToDirectoryOrUrl(dir, fileName, dir, f => host.getCanonicalFileName(f), /*isAbsolutePathAnUrl*/ false);
+        const dir = host.getCurrentDirectory();
+        const relativePath = getRelativePathToDirectoryOrUrl(dir, fileName, dir, f => host.getCanonicalFileName(f), /*isAbsolutePathAnUrl*/ false);
         return removeFileExtension(relativePath);
     }