From 86b55046c96d9c450a31397cac6465c6c9224962 Mon Sep 17 00:00:00 2001
From: Steve Sanderson <SteveSandersonMS@users.noreply.github.com>
Date: Tue, 9 Jul 2019 12:40:20 +0100
Subject: [PATCH] In JSInterop calls, use expected value for 'this'. Fixes
 dotnet/extensions#1477 (dotnet/extensions#1990)

\n\nCommit migrated from https://github.com/dotnet/extensions/commit/a664ecb5b3bcf9b2fdeb272e5e2705e8e43eeb9c
---
 .../src/src/Microsoft.JSInterop.ts                   | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/src/JSInterop/Microsoft.JSInterop.JS/src/src/Microsoft.JSInterop.ts b/src/JSInterop/Microsoft.JSInterop.JS/src/src/Microsoft.JSInterop.ts
index 5386b92bb5..2b3f51300c 100644
--- a/src/JSInterop/Microsoft.JSInterop.JS/src/src/Microsoft.JSInterop.ts
+++ b/src/JSInterop/Microsoft.JSInterop.JS/src/src/Microsoft.JSInterop.ts
@@ -141,14 +141,6 @@ module DotNet {
    * Receives incoming calls from .NET and dispatches them to JavaScript.
    */
   export const jsCallDispatcher = {
-    /**
-     * Finds the JavaScript function matching the specified identifier.
-     *
-     * @param identifier Identifies the globally-reachable function to be returned.
-     * @returns A Function instance.
-     */
-    findJSFunction,
-
     /**
      * Invokes the specified synchronous JavaScript function.
      *
@@ -227,8 +219,10 @@ module DotNet {
 
     let result: any = window;
     let resultIdentifier = 'window';
+    let lastSegmentValue: any;
     identifier.split('.').forEach(segment => {
       if (segment in result) {
+        lastSegmentValue = result;
         result = result[segment];
         resultIdentifier += '.' + segment;
       } else {
@@ -237,6 +231,8 @@ module DotNet {
     });
 
     if (result instanceof Function) {
+      result = result.bind(lastSegmentValue);
+      cachedJSFunctions[identifier] = result;
       return result;
     } else {
       throw new Error(`The value '${resultIdentifier}' is not a function.`);