From 98bb58964bec7dff0ccf481d474354ec1ca6f376 Mon Sep 17 00:00:00 2001
From: Richard Moore <github@ricmoo.com>
Date: Wed, 3 Jun 2020 03:33:28 -0400
Subject: [PATCH] Allow undefined properties in transaction object and fix
 stray this (#860).

---
 packages/contracts/src.ts/index.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/contracts/src.ts/index.ts b/packages/contracts/src.ts/index.ts
index 3619dc8474..23eba23347 100644
--- a/packages/contracts/src.ts/index.ts
+++ b/packages/contracts/src.ts/index.ts
@@ -231,7 +231,7 @@ async function populateTransaction(contract: Contract, fragment: FunctionFragmen
 
     // Make sure there are no stray overrides, which may indicate a
     // typo or using an unsupported key.
-    const leftovers = Object.keys(overrides);
+    const leftovers = Object.keys(overrides).filter((key) => ((<any>overrides)[key] != null));
     if (leftovers.length) {
         logger.throwError(`cannot override ${ leftovers.map((l) => JSON.stringify(l)).join(",") }`, Logger.errors.UNSUPPORTED_OPERATION, {
             operation: "overrides",
@@ -271,10 +271,10 @@ function buildCall(contract: Contract, fragment: FunctionFragment, collapseSimpl
         let blockTag = undefined;
         if (args.length === fragment.inputs.length + 1 && typeof(args[args.length - 1]) === "object") {
             const overrides = shallowCopy(args.pop());
-            if (overrides.blockTag) {
+            if (overrides.blockTag != null) {
                 blockTag = await overrides.blockTag;
-                delete overrides.blockTag;
             }
+            delete overrides.blockTag;
             args.push(overrides);
         }
 
@@ -337,7 +337,7 @@ function buildSend(contract: Contract, fragment: FunctionFragment): ContractFunc
                     if (parsed) {
                         event.args = parsed.args;
                         event.decode = (data: BytesLike, topics?: Array<any>) => {
-                            return this.interface.decodeEventLog(parsed.eventFragment, data, topics);
+                            return contract.interface.decodeEventLog(parsed.eventFragment, data, topics);
                         };
                         event.event = parsed.name;
                         event.eventSignature = parsed.signature;