Merge branch 'master' into no_ts_extension

src/compiler/core.ts

@@ -109,8 +109,8 @@ namespace ts {
         return undefined;
     }
 
-    /** Works like Array.prototype.find. */
-    export function find<T>(array: T[], predicate: (element: T, index: number) => boolean): T | undefined {
+    /** Works like Array.prototype.find, returning `undefined` if no element satisfying the predicate is found. */
+    export function tryFind<T>(array: T[], predicate: (element: T, index: number) => boolean): T | undefined {
         for (let i = 0, len = array.length; i < len; i++) {
             const value = array[i];
             if (predicate(value, i)) {
@@ -120,6 +120,17 @@ namespace ts {
         return undefined;
     }
 
+    /** Like `forEach`, but assumes existence of array and fails if no truthy value is found. */
+    export function find<T, U>(array: T[], callback: (element: T, index: number) => U | undefined): U {
+        for (let i = 0, len = array.length; i < len; i++) {
+            const result = callback(array[i], i);
+            if (result) {
+                return result;
+            }
+        }
+        Debug.fail();
+    }
+
     export function contains<T>(array: T[], value: T): boolean {
         if (array) {
             for (const v of array) {

src/compiler/utilities.ts

@@ -2715,7 +2715,7 @@ namespace ts {
 
     /** Return ".ts" or ".tsx" if that is the extension. */
     export function tryExtractTypeScriptExtension(fileName: string): string | undefined {
-        return find(supportedTypescriptExtensionsWithDtsFirst, extension => fileExtensionIs(fileName, extension));
+        return tryFind(supportedTypescriptExtensionsWithDtsFirst, extension => fileExtensionIs(fileName, extension));
     }
     // Must have '.d.ts' first because if '.ts' goes first, that will be detected as the extension instead of '.d.ts'.
     const supportedTypescriptExtensionsWithDtsFirst = supportedTypeScriptExtensions.slice().reverse();

src/harness/compilerRunner.ts

@@ -52,7 +52,7 @@ class CompilerBaselineRunner extends RunnerBase {
     private makeUnitName(name: string, root: string) {
         const path = ts.toPath(name, root, (fileName) => Harness.Compiler.getCanonicalFileName(fileName));
         const pathStart = ts.toPath(Harness.IO.getCurrentDirectory(), "", (fileName) => Harness.Compiler.getCanonicalFileName(fileName));
-        return pathStart === "" ? path : path.replace(pathStart, "/");
+        return pathStart ? path.replace(pathStart, "/") : path;
     };
 
     public checkTestCodeOutput(fileName: string) {