diff --git a/index.d.ts b/index.d.ts
index 12e1b4d1..c8e4ec24 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -1,3 +1,5 @@
+import type { WatchOptions } from 'chokidar'
+
 export type NodemonEventHandler =
   | 'start'
   | 'crash'
@@ -16,77 +18,34 @@ export type NodemonEventListener = {
   on(event: 'stdout' | 'stderr', listener: (e: string) => void): Nodemon;
   on(event: 'restart', listener: (e?: NodemonEventRestart) => void): Nodemon;
   on(event: 'quit', listener: (e?: NodemonEventQuit) => void): Nodemon;
-  on(event: 'exit', listener: (e?: NodemonEventExit) => void): Nodemon;
-  on(
-    event: 'config:update',
-    listener: (e?: NodemonEventConfig) => void
-  ): Nodemon;
+  on(event: 'exit', listener: (e?: number) => void): Nodemon;
+  on(event: 'config:update', listener: (e?: NodemonEventConfig) => void): Nodemon;
 };
 
 export type Nodemon = {
-  (options?: NodemonSettings): Nodemon;
-  on(event: 'start' | 'crash', listener: () => void): Nodemon;
-  on(event: 'log', listener: (e: NodemonEventLog) => void): Nodemon;
-  on(event: 'restart', listener: (e?: NodemonEventRestart) => void): Nodemon;
-  on(event: 'quit', listener: (e?: NodemonEventQuit) => void): Nodemon;
-  on(event: 'exit', listener: (e?: NodemonEventExit) => void): Nodemon;
-  on(
-    event: 'config:update',
-    listener: (e?: NodemonEventConfig) => void
-  ): Nodemon;
-
-  // this is repeated because VS Code doesn't autocomplete otherwise
-  addEventListener(event: 'start' | 'crash', listener: () => void): Nodemon;
-  addEventListener(
-    event: 'log',
-    listener: (e: NodemonEventLog) => void
-  ): Nodemon;
-  addEventListener(
-    event: 'restart',
-    listener: (e?: NodemonEventRestart) => void
-  ): Nodemon;
-  addEventListener(
-    event: 'quit',
-    listener: (e?: NodemonEventQuit) => void
-  ): Nodemon;
-  addEventListener(
-    event: 'exit',
-    listener: (e?: NodemonEventExit) => void
-  ): Nodemon;
-  addEventListener(
-    event: 'config:update',
-    listener: (e?: NodemonEventConfig) => void
-  ): Nodemon;
-
-  once(event: 'start' | 'crash', listener: () => void): Nodemon;
-  once(event: 'log', listener: (e: NodemonEventLog) => void): Nodemon;
-  once(event: 'restart', listener: (e?: NodemonEventRestart) => void): Nodemon;
-  once(event: 'quit', listener: (e?: NodemonEventQuit) => void): Nodemon;
-  once(event: 'exit', listener: (e?: NodemonEventExit) => void): Nodemon;
-  once(
-    event: 'config:update',
-    listener: (e?: NodemonEventConfig) => void
-  ): Nodemon;
-
   removeAllListeners(event: NodemonEventHandler): Nodemon;
   emit(type: NodemonEventHandler, event?: any): Nodemon;
   reset(callback: Function): Nodemon;
   restart(): Nodemon;
   config: NodemonSettings;
+} & NodemonEventListener & {
+  [K in keyof NodemonEventListener as "addListener"]: NodemonEventListener[K];
+} & {
+  [K in keyof NodemonEventListener as "once"]: NodemonEventListener[K];
 };
 
 export type NodemonEventLog = {
   /**
-    detail*: what you get with nodemon --verbose.
-    status: subprocess starting, restarting.
-    fail: is the subprocess crashing.
-    error: is a nodemon system error.
+    - detail: what you get with nodemon --verbose.
+    - status: subprocess starting, restarting.
+    - fail: is the subprocess crashing.
+    - error: is a nodemon system error.
   */
   type: 'detail' | 'log' | 'status' | 'error' | 'fail';
   /** the plain text message */
-  message: String;
+  message: string;
   /** contains the terminal escape codes to add colour, plus the "[nodemon]" prefix */
-  colour: String;
+  colour: string;
 };
 
 export interface NodemonEventRestart {
@@ -97,15 +56,36 @@ export interface NodemonEventRestart {
 }
 
 export type NodemonEventQuit = 143 | 130;
-export type NodemonEventExit = number;
 
-// TODO: Define the type of NodemonEventConfig
-export type NodemonEventConfig = any;
+export type NodemonEventConfig = {
+  run: boolean;
+  system: {
+    cwd: string;
+  };
+  required: boolean;
+  dirs: string[];
+  timeout: number;
+  options: NodemonConfig;
+  lastStarted: number
+  loaded: string[]
+  load: (settings: NodemonSettings, ready: (config: NodemonEventConfig) => void) => void
+  reset: () => void
+};
+
+export interface NodemonExecOptions {
+  script: string;
+  scriptPosition?: number;
+  args?: string[]
+  ext?: string; // "js,mjs" etc (should really support an array of strings, but I don't think it does right now)
+  exec?: string; // node, python, etc
+  execArgs?: string[]; // args passed to node, etc,
+  nodeArgs?: string[]; // args passed to node, etc,
+}
 
 export interface NodemonConfig {
-  /* restartable defaults to "rs" as a string the user enters */
-  restartable?: false | String;
-  colours?: Boolean;
+  /** restartable defaults to "rs" as a string the user enters */
+  restartable?: false | string;
+  colours?: boolean;
   execMap?: { [key: string]: string };
   ignoreRoot?: string[];
   watch?: string[];
@@ -116,25 +96,28 @@ export interface NodemonConfig {
   signal?: string;
   stdout?: boolean;
   watchOptions?: WatchOptions;
+  help?: string
+  version?: boolean
+  cwd?: string
+  dump?: boolean
+  ignore?: string[]
+  watch?: string[]
+  monitor?: string[]
+  spawn?: boolean
+  noUpdateNotifier?: boolean
+  legacyWatch?: boolean
+  pollingInterval?: number
+  /** @deprecated as this is "on" by default */
+  js?: boolean
+  quiet?: boolean
+  configFile?: string
+  exitCrash?: boolean
+  execOptions?: NodemonExecOptions
 }
 
-export interface NodemonSettings extends NodemonConfig {
-  script: string;
-  ext?: string; // "js,mjs" etc (should really support an array of strings, but I don't think it does right now)
+export interface NodemonSettings extends NodemonConfig, NodemonExecOptions {
   events?: { [key: string]: string };
   env?: { [key: string]: string };
-  exec?: string; // node, python, etc
-  execArgs?: string[]; // args passed to node, etc,
-  nodeArgs?: string[]; // args passed to node, etc,
-  delay?: number;
-}
-
-export interface WatchOptions {
-  ignorePermissionErrors: boolean;
-  ignored: string;
-  persistent: boolean;
-  usePolling: boolean;
-  interval: number;
 }
 
 const nodemon: Nodemon = (settings: NodemonSettings): Nodemon => {};
diff --git a/lib/cli/parse.js b/lib/cli/parse.js
index ad740038..560cc715 100644
--- a/lib/cli/parse.js
+++ b/lib/cli/parse.js
@@ -25,7 +25,7 @@ module.exports = parse;
  * Parses the command line arguments `process.argv` and returns the
  * nodemon options, the user script and the executable script.
  *
- * @param  {Array} full process arguments, including `node` leading arg
+ * @param  {Array<string> | string} argv full process arguments, including `node` leading arg
  * @return {Object} { options, script, args }
  */
 function parse(argv) {
@@ -97,9 +97,9 @@ function parse(argv) {
  * Given an argument (ie. from process.argv), sets nodemon
  * options and can eat up the argument value
  *
- * @param {Object} options object that will be updated
- * @param {Sting} current argument from argv
- * @param {Function} the callback to eat up the next argument in argv
+ * @param {import('../..').NodemonSettings} options object that will be updated
+ * @param {String} arg current argument from argv
+ * @param {Function} eatNext the callback to eat up the next argument in argv
  * @return {Boolean} false if argument was not a nodemon arg
  */
 function nodemonOption(options, arg, eatNext) {
@@ -161,7 +161,7 @@ function nodemonOption(options, arg, eatNext) {
   } else
 
   if (arg === '--exitcrash') {
-    options.exitcrash = true;
+    options.exitCrash = true;
   } else
 
   if (arg === '--delay' || arg === '-d') {
@@ -210,7 +210,7 @@ function nodemonOption(options, arg, eatNext) {
  * Given an argument (ie. from nodemonOption()), will parse and return the
  * equivalent millisecond value or 0 if the argument cannot be parsed
  *
- * @param {String} argument value given to the --delay option
+ * @param {String} value argument value given to the --delay option
  * @return {Number} millisecond equivalent of the argument
  */
 function parseDelay(value) {
diff --git a/lib/config/load.js b/lib/config/load.js
index 75d8443f..7c57d323 100644
--- a/lib/config/load.js
+++ b/lib/config/load.js
@@ -30,8 +30,10 @@ function findAppScript() {
  * the local nodemon.json to the exec and then overwriting using any user
  * specified settings (i.e. from the cli)
  *
- * @param  {Object} settings user defined settings
- * @param  {Function} ready    callback that receives complete config
+ * @param {Object} settings user defined settings
+ * @param {Object} options global options
+ * @param {Object} config the config object to be updated
+ * @param {Function} callback that receives complete config
  */
 function load(settings, options, config, callback) {
   config.loaded = [];
diff --git a/lib/monitor/run.js b/lib/monitor/run.js
index 52442033..4314226a 100644
--- a/lib/monitor/run.js
+++ b/lib/monitor/run.js
@@ -249,7 +249,7 @@ function run(options) {
       }
     } else {
       bus.emit('crash');
-      if (options.exitcrash) {
+      if (options.exitCrash) {
         utils.log.fail('app crashed');
         if (!config.required) {
           process.exit(1);
diff --git a/lib/nodemon.js b/lib/nodemon.js
index 278ea658..75619ba4 100644
--- a/lib/nodemon.js
+++ b/lib/nodemon.js
@@ -7,6 +7,7 @@ var util = require('util');
 var utils = require('./utils');
 var bus = utils.bus;
 var help = require('./help');
+/** @type {import('..').NodemonEventConfig} */
 var config = require('./config');
 var spawn = require('./spawn');
 const defaults = require('./config/defaults')
@@ -17,12 +18,15 @@ var eventHandlers = {};
 config.required = utils.isRequired;
 
 /**
- * @param {NodemonSettings} settings
- * @returns {Nodemon}
+ * @param {import('..').NodemonSettings | string} settings
+ * @returns {import('..').Nodemon}
  */
 function nodemon(settings) {
   bus.emit('boot');
   nodemon.reset();
+  
+  /** @type {import('..').NodemonSettings} */
+  let options
 
   // allow the cli string as the argument to nodemon, and allow for
   // `node nodemon -V app.js` or just `-V app.js`
@@ -34,25 +38,25 @@ function nodemon(settings) {
       }
       settings = 'node ' + settings;
     }
-    settings = cli.parse(settings);
-  }
+    options = cli.parse(settings);
+  } else options = settings;
 
   // set the debug flag as early as possible to get all the detailed logging
-  if (settings.verbose) {
+  if (options.verbose) {
     utils.debug = true;
   }
 
-  if (settings.help) {
+  if (options.help) {
     if (process.stdout.isTTY) {
       process.stdout._handle.setBlocking(true); // nodejs/node#6456
     }
-    console.log(help(settings.help));
+    console.log(help(options.help));
     if (!config.required) {
       process.exit(0);
     }
   }
 
-  if (settings.version) {
+  if (options.version) {
     version().then(function (v) {
       console.log(v);
       if (!config.required) {
@@ -65,17 +69,15 @@ function nodemon(settings) {
   // nodemon tools like grunt-nodemon. This affects where
   // the script is being run from, and will affect where
   // nodemon looks for the nodemon.json files
-  if (settings.cwd) {
+  if (options.cwd) {
     // this is protection to make sure we haven't dont the chdir already...
     // say like in cli/parse.js (which is where we do this once already!)
-    if (process.cwd() !== path.resolve(config.system.cwd, settings.cwd)) {
-      process.chdir(settings.cwd);
+    if (process.cwd() !== path.resolve(config.system.cwd, options.cwd)) {
+      process.chdir(options.cwd);
     }
   }
 
-  const cwd = process.cwd();
-
-  config.load(settings, function (config) {
+  config.load(options, function (config) {
     if (!config.options.dump && !config.options.execOptions.script &&
       config.options.execOptions.exec === 'node') {
       if (!config.required) {
@@ -175,7 +177,7 @@ function nodemon(settings) {
       // don't notify of default ignores
       if (defaults.ignoreRoot.indexOf(rule) !== -1) {
         return false;
-        return rule.slice(3).slice(0, -3);
+        // return rule.slice(3).slice(0, -3);
       }
 
       if (rule.startsWith(cwd)) {
diff --git a/lib/rules/add.js b/lib/rules/add.js
index de85bb7f..11f1fd71 100644
--- a/lib/rules/add.js
+++ b/lib/rules/add.js
@@ -28,7 +28,7 @@ module.exports = add;
  * @param {Object} rules containing `watch` and `ignore`. Also updated during
  *                       execution
  * @param {String} which must be either "watch" or "ignore"
- * @param {String|RegExp} the actual rule.
+ * @param {String|RegExp} rule the actual rule.
  */
 function add(rules, which, rule) {
   if (!{ ignore: 1, watch: 1}[which]) {
diff --git a/test/cli/parse.test.js b/test/cli/parse.test.js
index b2b63131..2b79971f 100644
--- a/test/cli/parse.test.js
+++ b/test/cli/parse.test.js
@@ -251,7 +251,7 @@ describe('nodemon argument parser', function () {
     assert(settings.exec === 'java', 'exec');
     assert(settings.quiet, 'quiet');
     assert(settings.stdin === false, 'read stdin');
-    assert(settings.exitcrash, 'exit if crash');
+    assert(settings.exitCrash, 'exit if crash');
     assert(settings.watch[0] === 'fixtures', 'watch');
     assert(settings.ignore[0] === 'fixtures', 'ignore');
     assert(settings.delay === 5000, 'delay 5 seconds');