diff --git a/packages/cli/src/bin/cli.test.ts b/packages/cli/src/bin/cli.test.ts
index ec0d24c9..3c722ee3 100644
--- a/packages/cli/src/bin/cli.test.ts
+++ b/packages/cli/src/bin/cli.test.ts
@@ -5,6 +5,7 @@ import http from 'http';
 import net from 'net';
 import path from 'path';
 import fs from 'fs';
+import execa from 'execa';
 import { version } from '../../package.json';
 import runCLI from '../testutils/';
 
@@ -146,9 +147,10 @@ describe('cli', () => {
       try {
         await runCLI(`file://${SIMPLE_HTML_FILE}`, '--exit');
       } catch (error) {
-        assert.equal(error.exitCode, 1);
+        const err = error as execa.ExecaReturnBase<string>;
+        assert.equal(err.exitCode, 1);
         assert.include(
-          error.stdout,
+          err.stdout,
           'Violation of "marquee" with 1 occurrences!'
         );
       }
@@ -158,9 +160,10 @@ describe('cli', () => {
       try {
         await runCLI(`file://${SIMPLE_CLEAN_HTML_FILE}`, '--exit');
       } catch (error) {
-        assert.equal(error.exitCode, 0);
+        const err = error as execa.ExecaReturnBase<string>;
+        assert.equal(err.exitCode, 0);
         assert.include(
-          error.stdout,
+          err.stdout,
           'Violation of "marquee" with 1 occurrences!'
         );
       }
@@ -382,9 +385,10 @@ describe('cli', () => {
       try {
         await runCLI(`file://${SIMPLE_HTML_FILE}`, '--timeout', '0');
       } catch (error) {
-        assert.notEqual(error.exitCode, 0);
+        const err = error as execa.ExecaReturnBase<string>;
+        assert.notEqual(err.exitCode, 0);
         assert.include(
-          error.stderr,
+          err.stderr,
           'An error occurred while testing this page.'
         );
       }
diff --git a/packages/cli/src/lib/axe-test-urls.ts b/packages/cli/src/lib/axe-test-urls.ts
index 94838187..ff423f30 100644
--- a/packages/cli/src/lib/axe-test-urls.ts
+++ b/packages/cli/src/lib/axe-test-urls.ts
@@ -67,7 +67,7 @@ const testPages = async (
           events?.startTimer('axe-core execution time');
         }
 
-        axe.analyze((err: Error | null, results: AxeResults) => {
+        axe.analyze((err, results) => {
           if (config.timer) {
             events?.endTimer('axe-core execution time');
           }
@@ -83,7 +83,7 @@ const testPages = async (
           }
 
           // Move to the next item
-          testPages(urls.slice(1), config, events).then((out: AxeResults) => {
+          testPages(urls.slice(1), config, events).then(out => {
             resolve([results].concat(out));
           });
         });
diff --git a/packages/cli/tsconfig.json b/packages/cli/tsconfig.json
index 67909205..e7ced076 100644
--- a/packages/cli/tsconfig.json
+++ b/packages/cli/tsconfig.json
@@ -1,19 +1,11 @@
 {
+  "extends": "../../tsconfig.json",
   "compilerOptions": {
-    "types": ["node"],
-    "outDir": "./dist/",
-    "sourceMap": true,
-    "noImplicitAny": true,
-    "strictNullChecks": true,
-    "moduleResolution": "node",
-    "resolveJsonModule": true,
+    "lib": ["dom", "ES2015", "esnext.asynciterable"],
     "module": "commonjs",
+    "outDir": "./dist/",
     "target": "ES2015",
-    "allowJs": true,
-    "lib": ["dom", "ES2015", "esnext.asynciterable"],
-    "esModuleInterop": true,
-    "skipLibCheck": true,
-    "declaration": true
+    "types": ["node"]
   },
   "include": ["./src/lib", "./src/bin"]
 }
diff --git a/packages/playwright/src/index.ts b/packages/playwright/src/index.ts
index 3b653ed8..53cf8e01 100644
--- a/packages/playwright/src/index.ts
+++ b/packages/playwright/src/index.ts
@@ -310,6 +310,7 @@ export default class AxeBuilder {
       if (result.length > sizeLimit) {
         return await chunkResults(result.substr(sizeLimit));
       }
+      return;
     }
 
     await chunkResults(partialString);
diff --git a/packages/puppeteer/src/axePuppeteer.ts b/packages/puppeteer/src/axePuppeteer.ts
index ff02e06c..4eb2a196 100644
--- a/packages/puppeteer/src/axePuppeteer.ts
+++ b/packages/puppeteer/src/axePuppeteer.ts
@@ -294,6 +294,7 @@ export class AxePuppeteer {
       if (result.length > sizeLimit) {
         return await chunkResults(result.substr(sizeLimit));
       }
+      return;
     }
 
     await chunkResults(partialString);
diff --git a/packages/puppeteer/tsconfig.json b/packages/puppeteer/tsconfig.json
index 43fc2c19..971582be 100644
--- a/packages/puppeteer/tsconfig.json
+++ b/packages/puppeteer/tsconfig.json
@@ -1,24 +1,7 @@
 {
+  "extends": "../../tsconfig.json",
   "compilerOptions": {
-    /* Basic Options */
-    "target": "esnext",
-    "module": "commonjs" /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */,
-    "lib": [
-      "dom",
-      "esnext"
-    ] /* Specify library files to be included in the compilation. */,
-    "declaration": true /* Generates corresponding '.d.ts' file. */,
-    "sourceMap": true /* Generates corresponding '.map' file. */,
-    "outDir": "dist" /* Redirect output structure to the directory. */,
-    "rootDir": "src" /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */,
-    "removeComments": true /* Do not emit comments to output. */,
-    "pretty": true,
-    "strict": true,
-    "noImplicitAny": true,
-    "noImplicitThis": true,
-    "noImplicitReturns": true,
-    "moduleResolution": "node",
-    "esModuleInterop": true
+    "module": "commonjs"
   },
   "include": ["src"]
 }
diff --git a/packages/webdriverio/src/utils.ts b/packages/webdriverio/src/utils.ts
index a47f2bae..a9e37df7 100644
--- a/packages/webdriverio/src/utils.ts
+++ b/packages/webdriverio/src/utils.ts
@@ -217,6 +217,7 @@ export const axeFinishRun = (
       if (result.length > sizeLimit) {
         return chunkResults(result.substr(sizeLimit));
       }
+      return;
     });
   }
 
diff --git a/packages/webdriverjs/src/browser.ts b/packages/webdriverjs/src/browser.ts
index 71f57590..8c9c50f0 100644
--- a/packages/webdriverjs/src/browser.ts
+++ b/packages/webdriverjs/src/browser.ts
@@ -79,6 +79,7 @@ export function axeFinishRun(
       if (result.length > sizeLimit) {
         return chunkResults(result.substr(sizeLimit));
       }
+      return;
     });
   }
 
diff --git a/packages/webdriverjs/src/types.ts b/packages/webdriverjs/src/types.ts
index 9abfc8e0..ba286c0e 100644
--- a/packages/webdriverjs/src/types.ts
+++ b/packages/webdriverjs/src/types.ts
@@ -18,8 +18,7 @@ export interface AxeInjectorParams extends Options {
 }
 
 export type CallbackFunction = (
-  error: Error | null,
-  results: AxeResults | null
+  ...args: [Error, null] | [null, AxeResults]
 ) => void;
 
 export type InjectCallback = (err?: Error) => void;
diff --git a/tsconfig.json b/tsconfig.json
index a076ed9f..96cc6522 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,21 +1,30 @@
 {
   "compilerOptions": {
-    "moduleResolution": "node",
-    "target": "esnext",
-    "module": "esnext",
+    "allowJs": true,
+    "declaration": true,
+    "esModuleInterop": true,
     "lib": ["dom", "esnext"],
-    "strict": true,
+    "module": "esnext",
+    "moduleResolution": "node",
+    "noImplicitAny": true,
+    "noImplicitReturns": true,
+    "noImplicitThis": true,
+    "outDir": "dist",
     "pretty": true,
+    "removeComments": true,
+    "resolveJsonModule": true,
+    "skipLibCheck": true,
     "sourceMap": true,
-    "declaration": true,
-    "outDir": "dist",
-    "esModuleInterop": true,
-    "resolveJsonModule": true
+    "strict": true,
+    "strictNullChecks": true,
+    "target": "esnext"
   },
+  "exclude": ["**/*.test.ts", "**/test/**/*.ts"],
   "ts-node": {
     "compilerOptions": {
       "module": "commonjs",
-      "target": "es5"
+      "target": "es5",
+      "removeComments": false
     }
   }
 }