From 9e84d720e6e881cecc34f5e0d87fbe291b9eba17 Mon Sep 17 00:00:00 2001
From: David Sherret <dsherret@gmail.com>
Date: Sat, 20 Nov 2021 20:09:22 -0500
Subject: [PATCH] fix: align `getScriptSnapshot` compiler host libFileMap
 behaviour with `readFile`

---
 deno/common/ts_morph_common.js              | 16 +++++++---------
 packages/common/src/compiler/createHosts.ts | 18 ++++++++----------
 2 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/deno/common/ts_morph_common.js b/deno/common/ts_morph_common.js
index 582b87aad..298cfe417 100644
--- a/deno/common/ts_morph_common.js
+++ b/deno/common/ts_morph_common.js
@@ -1034,18 +1034,16 @@ function createHosts(options) {
         },
         getScriptSnapshot: fileName => {
             const filePath = transactionalFileSystem.getStandardizedAbsolutePath(fileName);
-            if (!fileExistsSync(filePath)) {
-                if (libFileMap != null) {
-                    const libFileText = libFileMap.get(filePath);
-                    if (libFileText != null)
-                        return ts.ScriptSnapshot.fromString(libFileText);
-                }
-                return undefined;
+            if (libFileMap != null) {
+                const libFileText = libFileMap.get(filePath);
+                if (libFileText != null)
+                    return ts.ScriptSnapshot.fromString(libFileText);
             }
-            return ts.ScriptSnapshot.fromString(sourceFileContainer.addOrGetSourceFileFromFilePathSync(filePath, {
+            const sourceFile = sourceFileContainer.addOrGetSourceFileFromFilePathSync(filePath, {
                 markInProject: false,
                 scriptKind: undefined,
-            }).getFullText());
+            });
+            return sourceFile ? ts.ScriptSnapshot.fromString(sourceFile.getFullText()) : undefined;
         },
         getCurrentDirectory: () => transactionalFileSystem.getCurrentDirectory(),
         getDefaultLibFileName: options => {
diff --git a/packages/common/src/compiler/createHosts.ts b/packages/common/src/compiler/createHosts.ts
index 8a43e37bb..84d46d525 100644
--- a/packages/common/src/compiler/createHosts.ts
+++ b/packages/common/src/compiler/createHosts.ts
@@ -65,19 +65,17 @@ export function createHosts(options: CreateHostsOptions) {
     },
     getScriptSnapshot: fileName => {
       const filePath = transactionalFileSystem.getStandardizedAbsolutePath(fileName);
-      if (!fileExistsSync(filePath)) {
-        if (libFileMap != null) {
-          const libFileText = libFileMap.get(filePath);
-          if (libFileText != null)
-            return ts.ScriptSnapshot.fromString(libFileText);
-        }
-
-        return undefined;
+      if (libFileMap != null) {
+        const libFileText = libFileMap.get(filePath);
+        if (libFileText != null)
+          return ts.ScriptSnapshot.fromString(libFileText);
       }
-      return ts.ScriptSnapshot.fromString(sourceFileContainer.addOrGetSourceFileFromFilePathSync(filePath, {
+
+      const sourceFile = sourceFileContainer.addOrGetSourceFileFromFilePathSync(filePath, {
         markInProject: false,
         scriptKind: undefined,
-      })!.getFullText());
+      });
+      return sourceFile ? ts.ScriptSnapshot.fromString(sourceFile.getFullText()) : undefined;
     },
     getCurrentDirectory: () => transactionalFileSystem.getCurrentDirectory(),
     getDefaultLibFileName: options => {