3 files changed, 32 insertions, 17 deletions

diff --git a/std/encoding/csv.ts b/std/encoding/csv.ts
index cc486641b..1314afcaa 100644
--- a/std/encoding/csv.ts
+++ b/std/encoding/csv.ts
@@ -5,6 +5,7 @@
 import { BufReader } from "../io/bufio.ts";
 import { TextProtoReader } from "../textproto/mod.ts";
 import { StringReader } from "../io/readers.ts";
+import { assert } from "../testing/asserts.ts";
 
 const INVALID_RUNE = ["\r", "\n", '"'];
 
@@ -37,11 +38,15 @@ export interface ReadOptions {
 }
 
 function chkOptions(opt: ReadOptions): void {
-  if (!opt.comma) opt.comma = ",";
-  if (!opt.trimLeadingSpace) opt.trimLeadingSpace = false;
+  if (!opt.comma) {
+    opt.comma = ",";
+  }
+  if (!opt.trimLeadingSpace) {
+    opt.trimLeadingSpace = false;
+  }
   if (
-    INVALID_RUNE.includes(opt.comma!) ||
-    INVALID_RUNE.includes(opt.comment!) ||
+    INVALID_RUNE.includes(opt.comma) ||
+    INVALID_RUNE.includes(opt.comment) ||
     opt.comma === opt.comment
   ) {
     throw new Error("Invalid Delimiter");
@@ -81,7 +86,8 @@ async function read(
     return [];
   }
 
-  result = line.split(opt.comma!);
+  assert(opt.comma != null);
+  result = line.split(opt.comma);
 
   let quoteError = false;
   result = result.map((r): string => {
@@ -141,7 +147,7 @@ export async function readMatrix(
     }
 
     if (lineResult.length > 0) {
-      if (_nbFields! && _nbFields! !== lineResult.length) {
+      if (_nbFields && _nbFields !== lineResult.length) {
         throw new ParseError(lineIndex, lineIndex, "wrong number of fields");
       }
       result.push(lineResult);
@@ -215,7 +221,9 @@ export async function parse(
         );
       }
     } else {
-      headers = r.shift()!.map(
+      const head = r.shift();
+      assert(head != null);
+      headers = head.map(
         (e): HeaderOptions => {
           return {
             name: e
@@ -245,7 +253,8 @@ export async function parse(
     });
   }
   if (opt.parse) {
-    return r.map((e: string[]): unknown => opt.parse!(e));
+    assert(opt.parse != null, "opt.parse must be set");
+    return r.map((e: string[]): unknown => opt.parse(e));
   }
   return r;
 }
diff --git a/std/encoding/csv_test.ts b/std/encoding/csv_test.ts
index daa30d0fb..6c726835e 100644
--- a/std/encoding/csv_test.ts
+++ b/std/encoding/csv_test.ts
@@ -477,7 +477,7 @@ for (const t of testCases) {
       if (t.Error) {
         let err;
         try {
-          actual = await readMatrix(new BufReader(new StringReader(t.Input!)), {
+          actual = await readMatrix(new BufReader(new StringReader(t.Input)), {
             comma: comma,
             comment: comment,
             trimLeadingSpace: trim,
@@ -490,7 +490,7 @@ for (const t of testCases) {
         assert(err);
         assertEquals(err.message, t.Error);
       } else {
-        actual = await readMatrix(new BufReader(new StringReader(t.Input!)), {
+        actual = await readMatrix(new BufReader(new StringReader(t.Input)), {
           comma: comma,
           comment: comment,
           trimLeadingSpace: trim,
diff --git a/std/encoding/toml.ts b/std/encoding/toml.ts
index 6af31a1a1..53b907fbf 100644
--- a/std/encoding/toml.ts
+++ b/std/encoding/toml.ts
@@ -1,6 +1,7 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import { deepAssign } from "../util/deep_assign.ts";
 import { pad } from "../strings/pad.ts";
+import { assert } from "../testing/asserts.ts";
 
 class KeyValuePair {
   constructor(public key: string, public value: unknown) {}
@@ -138,15 +139,16 @@ class Parser {
     }
   }
   _groupToOutput(): void {
-    const arrProperty = this.context
-      .currentGroup!.name.replace(/"/g, "")
+    assert(this.context.currentGroup != null, "currentGroup must be set");
+    const arrProperty = this.context.currentGroup.name
+      .replace(/"/g, "")
       .replace(/'/g, "")
       .split(".");
     let u = {};
-    if (this.context.currentGroup!.type === "array") {
-      u = this._unflat(arrProperty, this.context.currentGroup!.arrValues);
+    if (this.context.currentGroup.type === "array") {
+      u = this._unflat(arrProperty, this.context.currentGroup.arrValues);
     } else {
-      u = this._unflat(arrProperty, this.context.currentGroup!.objValues);
+      u = this._unflat(arrProperty, this.context.currentGroup.objValues);
     }
     deepAssign(this.context.output, u);
     delete this.context.currentGroup;
@@ -170,10 +172,14 @@ class Parser {
     }
 
     let type;
-    let name = line.match(captureReg)![1];
+    let m = line.match(captureReg);
+    assert(m != null, "line mut be matched");
+    let name = m[1];
     if (name.match(/\[.*\]/)) {
       type = "array";
-      name = name.match(captureReg)![1];
+      m = name.match(captureReg);
+      assert(m != null, "name must be matched");
+      name = m[1];
     } else {
       type = "object";
     }