diff --git a/lib/components/searchBox.js b/lib/components/searchBox.tsx
similarity index 80%
rename from lib/components/searchBox.js
rename to lib/components/searchBox.tsx
index a172cbce..201ce12d 100644
--- a/lib/components/searchBox.js
+++ b/lib/components/searchBox.tsx
@@ -1,6 +1,7 @@
 import React from 'react';
+import {SearchBoxProps} from '../hyper';
 
-const searchBoxStyling = {
+const searchBoxStyling: React.CSSProperties = {
   float: 'right',
   height: '28px',
   backgroundColor: 'white',
@@ -8,21 +9,22 @@ const searchBoxStyling = {
   right: '10px',
   top: '25px',
   width: '224px',
-  zIndex: '9999'
+  zIndex: 9999
 };
 
 const enterKey = 13;
 
-export default class SearchBox extends React.PureComponent {
-  constructor(props) {
+export default class SearchBox extends React.PureComponent<SearchBoxProps> {
+  searchTerm: string;
+  constructor(props: SearchBoxProps) {
     super(props);
     this.searchTerm = '';
   }
 
-  handleChange = event => {
-    this.searchTerm = event.target.value;
+  handleChange = (event: React.KeyboardEvent<HTMLInputElement>) => {
+    this.searchTerm = event.currentTarget.value;
     if (event.keyCode === enterKey) {
-      this.props.search(event.target.value);
+      this.props.search(event.currentTarget.value);
     }
   };
 
diff --git a/lib/components/term.js b/lib/components/term.tsx
similarity index 81%
rename from lib/components/term.js
rename to lib/components/term.tsx
index bfc61206..c915cf78 100644
--- a/lib/components/term.js
+++ b/lib/components/term.tsx
@@ -1,15 +1,18 @@
 import React from 'react';
-import {Terminal} from 'xterm';
+import {Terminal, ITerminalOptions, IDisposable} from 'xterm';
 import {FitAddon} from 'xterm-addon-fit';
 import {WebLinksAddon} from 'xterm-addon-web-links';
 import {SearchAddon} from 'xterm-addon-search';
 import {WebglAddon} from 'xterm-addon-webgl';
 import {LigaturesAddon} from 'xterm-addon-ligatures';
 import {clipboard} from 'electron';
-import * as Color from 'color';
+import Color from 'color';
 import terms from '../terms';
 import processClipboard from '../utils/paste';
 import SearchBox from './searchBox';
+import ResizeObserver from 'resize-observer-polyfill';
+import {TermProps} from '../hyper';
+import {ObjectTypedKeys} from '../utils/object';
 
 const isWindows = ['Windows', 'Win16', 'Win32', 'WinCE'].includes(navigator.platform);
 
@@ -18,7 +21,7 @@ const CURSOR_STYLES = {
   BEAM: 'bar',
   UNDERLINE: 'underline',
   BLOCK: 'block'
-};
+} as const;
 
 const isWebgl2Supported = (() => {
   let isSupported = window.WebGL2RenderingContext ? undefined : false;
@@ -32,7 +35,7 @@ const isWebgl2Supported = (() => {
   };
 })();
 
-const getTermOptions = props => {
+const getTermOptions = (props: TermProps): ITerminalOptions => {
   // Set a background color only if it is opaque
   const needTransparency = Color(props.backgroundColor).alpha() < 1;
   const backgroundColor = needTransparency ? 'transparent' : props.backgroundColor;
@@ -78,13 +81,23 @@ const getTermOptions = props => {
   };
 };
 
-export default class Term extends React.PureComponent {
-  constructor(props) {
+export default class Term extends React.PureComponent<TermProps> {
+  termRef: HTMLElement | null;
+  termWrapperRef: HTMLElement | null;
+  termOptions: ITerminalOptions;
+  disposableListeners: IDisposable[];
+  termDefaultBellSound: string | null;
+  fitAddon: FitAddon;
+  searchAddon: SearchAddon;
+  static rendererTypes: Record<string, string>;
+  term!: Terminal;
+  resizeObserver!: ResizeObserver;
+  resizeTimeout!: NodeJS.Timeout;
+  constructor(props: TermProps) {
     super(props);
     props.ref_(props.uid, this);
     this.termRef = null;
     this.termWrapperRef = null;
-    this.termRect = null;
     this.termOptions = {};
     this.disposableListeners = [];
     this.termDefaultBellSound = null;
@@ -93,7 +106,7 @@ export default class Term extends React.PureComponent {
   }
 
   // The main process shows this in the About dialog
-  static reportRenderer(uid, type) {
+  static reportRenderer(uid: string, type: string) {
     const rendererTypes = Term.rendererTypes || {};
     if (rendererTypes[uid] !== type) {
       rendererTypes[uid] = type;
@@ -111,14 +124,14 @@ export default class Term extends React.PureComponent {
 
     // The parent element for the terminal is attached and removed manually so
     // that we can preserve it across mounts and unmounts of the component
-    this.termRef = props.term ? props.term.element.parentElement : document.createElement('div');
+    this.termRef = props.term ? props.term.element!.parentElement! : document.createElement('div');
     this.termRef.className = 'term_fit term_term';
 
-    this.termWrapperRef.appendChild(this.termRef);
+    this.termWrapperRef?.appendChild(this.termRef);
 
     if (!props.term) {
-      let needTransparency = Color(props.backgroundColor).alpha() < 1;
-      let useWebGL = false;
+      const needTransparency = Color(props.backgroundColor).alpha() < 1;
+      const useWebGL = false;
       if (props.webGLRenderer) {
         if (needTransparency) {
           console.warn(
@@ -148,8 +161,8 @@ export default class Term extends React.PureComponent {
       }
     } else {
       // get the cached plugins
-      this.fitAddon = props.fitAddon;
-      this.searchAddon = props.searchAddon;
+      this.fitAddon = props.fitAddon!;
+      this.searchAddon = props.searchAddon!;
     }
 
     this.fitAddon.fit();
@@ -163,9 +176,9 @@ export default class Term extends React.PureComponent {
     }
 
     if (props.onActive) {
-      this.term.textarea.addEventListener('focus', props.onActive);
+      this.term.textarea?.addEventListener('focus', props.onActive);
       this.disposableListeners.push({
-        dispose: () => this.term.textarea.removeEventListener('focus', this.props.onActive)
+        dispose: () => this.term.textarea?.removeEventListener('focus', this.props.onActive)
       });
     }
 
@@ -188,14 +201,14 @@ export default class Term extends React.PureComponent {
       this.disposableListeners.push(
         this.term.onCursorMove(() => {
           const cursorFrame = {
-            x: this.term.buffer.cursorX * this.term._core._renderService.dimensions.actualCellWidth,
-            y: this.term.buffer.cursorY * this.term._core._renderService.dimensions.actualCellHeight,
-            width: this.term._core._renderService.dimensions.actualCellWidth,
-            height: this.term._core._renderService.dimensions.actualCellHeight,
+            x: this.term.buffer.cursorX * (this.term as any)._core._renderService.dimensions.actualCellWidth,
+            y: this.term.buffer.cursorY * (this.term as any)._core._renderService.dimensions.actualCellHeight,
+            width: (this.term as any)._core._renderService.dimensions.actualCellWidth,
+            height: (this.term as any)._core._renderService.dimensions.actualCellHeight,
             col: this.term.buffer.cursorX,
             row: this.term.buffer.cursorY
           };
-          props.onCursorMove(cursorFrame);
+          props.onCursorMove?.(cursorFrame);
         })
       );
     }
@@ -220,18 +233,18 @@ export default class Term extends React.PureComponent {
 
   // intercepting paste event for any necessary processing of
   // clipboard data, if result is falsy, paste event continues
-  onWindowPaste = e => {
+  onWindowPaste = (e: any) => {
     if (!this.props.isTermActive) return;
 
     const processed = processClipboard();
     if (processed) {
       e.preventDefault();
       e.stopPropagation();
-      this.term._core.handler(processed);
+      (this.term as any)._core.handler(processed);
     }
   };
 
-  onMouseUp = e => {
+  onMouseUp = (e: React.MouseEvent) => {
     if (this.props.quickEdit && e.button === 2) {
       if (this.term.hasSelection()) {
         clipboard.writeText(this.term.getSelection());
@@ -244,7 +257,7 @@ export default class Term extends React.PureComponent {
     }
   };
 
-  write(data) {
+  write(data: string | Uint8Array) {
     this.term.write(data);
   }
 
@@ -260,15 +273,15 @@ export default class Term extends React.PureComponent {
     this.term.reset();
   }
 
-  search = searchTerm => {
+  search = (searchTerm = '') => {
     this.searchAddon.findNext(searchTerm);
   };
 
-  searchNext = searchTerm => {
+  searchNext = (searchTerm: string) => {
     this.searchAddon.findNext(searchTerm);
   };
 
-  searchPrevious = searchTerm => {
+  searchPrevious = (searchTerm: string) => {
     this.searchAddon.findPrevious(searchTerm);
   };
 
@@ -276,7 +289,7 @@ export default class Term extends React.PureComponent {
     this.props.toggleSearch();
   };
 
-  resize(cols, rows) {
+  resize(cols: number, rows: number) {
     this.term.resize(cols, rows);
   }
 
@@ -291,12 +304,12 @@ export default class Term extends React.PureComponent {
     this.fitAddon.fit();
   }
 
-  keyboardHandler(e) {
+  keyboardHandler(e: any) {
     // Has Mousetrap flagged this event as a command?
     return !e.catched;
   }
 
-  componentDidUpdate(prevProps) {
+  componentDidUpdate(prevProps: TermProps) {
     if (!prevProps.cleared && this.props.cleared) {
       this.clear();
     }
@@ -305,14 +318,14 @@ export default class Term extends React.PureComponent {
 
     // Use bellSound in nextProps if it exists
     // otherwise use the default sound found in xterm.
-    nextTermOptions.bellSound = this.props.bellSound || this.termDefaultBellSound;
+    nextTermOptions.bellSound = this.props.bellSound || this.termDefaultBellSound!;
 
     if (!prevProps.search && this.props.search) {
       this.search();
     }
 
     // Update only options that have changed.
-    Object.keys(nextTermOptions)
+    ObjectTypedKeys(nextTermOptions)
       .filter(option => option !== 'theme' && nextTermOptions[option] !== this.termOptions[option])
       .forEach(option => {
         try {
@@ -330,8 +343,8 @@ export default class Term extends React.PureComponent {
     const shouldUpdateTheme =
       !this.termOptions.theme ||
       nextTermOptions.rendererType !== this.termOptions.rendererType ||
-      Object.keys(nextTermOptions.theme).some(
-        option => nextTermOptions.theme[option] !== this.termOptions.theme[option]
+      ObjectTypedKeys(nextTermOptions.theme!).some(
+        option => nextTermOptions.theme![option] !== this.termOptions.theme![option]
       );
     if (shouldUpdateTheme) {
       this.term.setOption('theme', nextTermOptions.theme);
@@ -350,11 +363,11 @@ export default class Term extends React.PureComponent {
     }
 
     if (prevProps.rows !== this.props.rows || prevProps.cols !== this.props.cols) {
-      this.resize(this.props.cols, this.props.rows);
+      this.resize(this.props.cols!, this.props.rows!);
     }
   }
 
-  onTermWrapperRef = component => {
+  onTermWrapperRef = (component: HTMLElement | null) => {
     this.termWrapperRef = component;
 
     if (component) {
@@ -372,7 +385,7 @@ export default class Term extends React.PureComponent {
 
   componentWillUnmount() {
     terms[this.props.uid] = null;
-    this.termWrapperRef.removeChild(this.termRef);
+    this.termWrapperRef?.removeChild(this.termRef!);
     this.props.ref_(this.props.uid, null);
 
     // to clean up the terminal, we remove the listeners
diff --git a/lib/components/terms.js b/lib/components/terms.tsx
similarity index 84%
rename from lib/components/terms.js
rename to lib/components/terms.tsx
index 4ecb5017..a41e1634 100644
--- a/lib/components/terms.js
+++ b/lib/components/terms.tsx
@@ -3,62 +3,53 @@ import {decorate, getTermGroupProps} from '../utils/plugins';
 import {registerCommandHandlers} from '../command-registry';
 import TermGroup_ from './term-group';
 import StyleSheet_ from './style-sheet';
+import {TermsProps} from '../hyper';
+import Term from './term';
+import {ObjectTypedKeys} from '../utils/object';
 
 const TermGroup = decorate(TermGroup_, 'TermGroup');
 const StyleSheet = decorate(StyleSheet_, 'StyleSheet');
 
 const isMac = /Mac/.test(navigator.userAgent);
 
-export default class Terms extends React.Component {
-  constructor(props, context) {
+export default class Terms extends React.Component<TermsProps> {
+  terms: Record<string, Term>;
+  registerCommands: (cmds: Record<string, (...args: any[]) => void>) => void;
+  constructor(props: TermsProps, context: any) {
     super(props, context);
     this.terms = {};
-    this.bound = new WeakMap();
     this.registerCommands = registerCommandHandlers;
     props.ref_(this);
   }
 
-  shouldComponentUpdate(nextProps) {
-    for (const i in nextProps) {
-      if (i === 'write') {
-        continue;
-      }
-      if (this.props[i] !== nextProps[i]) {
-        return true;
-      }
-    }
-    for (const i in this.props) {
-      if (i === 'write') {
-        continue;
-      }
-      if (this.props[i] !== nextProps[i]) {
-        return true;
-      }
-    }
-    return false;
+  shouldComponentUpdate(nextProps: TermsProps & {children: any}) {
+    return (
+      ObjectTypedKeys(nextProps).some(i => i !== 'write' && this.props[i] !== nextProps[i]) ||
+      ObjectTypedKeys(this.props).some(i => i !== 'write' && this.props[i] !== nextProps[i])
+    );
   }
 
-  onRef = (uid, term) => {
+  onRef = (uid: string, term: Term) => {
     if (term) {
       this.terms[uid] = term;
     }
   };
 
-  getTermByUid(uid) {
+  getTermByUid(uid: string) {
     return this.terms[uid];
   }
 
   getActiveTerm() {
-    return this.getTermByUid(this.props.activeSession);
+    return this.getTermByUid(this.props.activeSession!);
   }
 
-  onTerminal(uid, term) {
+  onTerminal(uid: string, term: Term) {
     this.terms[uid] = term;
   }
 
   componentDidMount() {
     window.addEventListener('contextmenu', () => {
-      const selection = window.getSelection().toString();
+      const selection = window.getSelection()!.toString();
       const {
         props: {uid}
       } = this.getActiveTerm();
@@ -66,8 +57,8 @@ export default class Terms extends React.Component {
     });
   }
 
-  componentDidUpdate(prevProps) {
-    for (let uid in prevProps.sessions) {
+  componentDidUpdate(prevProps: TermsProps) {
+    for (const uid in prevProps.sessions) {
       if (!this.props.sessions[uid]) {
         this.terms[uid].term.dispose();
         delete this.terms[uid];
diff --git a/lib/hyper.d.ts b/lib/hyper.d.ts
index 0d0cc3ac..1524f94d 100644
--- a/lib/hyper.d.ts
+++ b/lib/hyper.d.ts
@@ -26,7 +26,7 @@ export type ITermState = {
 };
 
 export type cursorShapes = 'BEAM' | 'UNDERLINE' | 'BLOCK';
-import {FontWeight} from 'xterm';
+import {FontWeight, Terminal} from 'xterm';
 
 export type uiState = {
   _lastUpdate: number | null;
@@ -221,7 +221,7 @@ export type TabProps = {
   isActive: boolean;
   isFirst: boolean;
   isLast: boolean;
-  onClick: (event: React.MouseEvent<HTMLElement, MouseEvent>) => void;
+  onClick?: (event: React.MouseEvent<HTMLElement, MouseEvent>) => void;
   onClose: () => void;
   onSelect: () => void;
   text: string;
@@ -237,8 +237,8 @@ export type ITab = {
 export type TabsProps = {
   tabs: ITab[];
   borderColor: string;
-  onChange: () => void;
-  onClose: () => void;
+  onChange: (uid: string) => void;
+  onClose: (uid: string) => void;
   fullScreen: boolean;
 } & extensionProps;
 
@@ -312,3 +312,62 @@ export type TermGroupOwnProps = {
 
 import {TermGroupConnectedProps} from './components/term-group';
 export type TermGroupProps = TermGroupConnectedProps & TermGroupOwnProps;
+
+export type SearchBoxProps = {
+  search: (searchTerm: string) => void;
+  next: (searchTerm: string) => void;
+  prev: (searchTerm: string) => void;
+  close: () => void;
+};
+
+import {FitAddon} from 'xterm-addon-fit';
+import {SearchAddon} from 'xterm-addon-search';
+export type TermProps = {
+  backgroundColor: string;
+  bell: string;
+  bellSound: string | null;
+  bellSoundURL: string | null;
+  borderColor: string;
+  cleared: boolean;
+  colors: uiState['colors'];
+  cols: number | null;
+  copyOnSelect: boolean;
+  cursorAccentColor?: string;
+  cursorBlink: boolean;
+  cursorColor: string;
+  cursorShape: cursorShapes;
+  disableLigatures: boolean;
+  fitAddon: FitAddon | null;
+  fontFamily: string;
+  fontSize: number;
+  fontSmoothing?: string;
+  fontWeight: FontWeight;
+  fontWeightBold: FontWeight;
+  foregroundColor: string;
+  isTermActive: boolean;
+  letterSpacing: number;
+  lineHeight: number;
+  macOptionSelectionMode: string;
+  modifierKeys: Immutable<{altIsMeta: boolean; cmdIsMeta: boolean}>;
+  onActive: () => void;
+  onContextMenu: (selection: any) => void;
+  onCursorMove?: (cursorFrame: {x: number; y: number; width: number; height: number; col: number; row: number}) => void;
+  onData: (data: any) => void;
+  onResize: (cols: number, rows: number) => void;
+  onTitle: (title: string) => void;
+  padding: string;
+  quickEdit: boolean;
+  rows: number | null;
+  scrollback: number;
+  search: boolean;
+  searchAddon: SearchAddon | null;
+  selectionColor: string;
+  term: Terminal | null;
+  toggleSearch: () => void;
+  uid: string;
+  uiFontFamily: string;
+  url: string | null;
+  webGLRenderer: boolean;
+} & extensionProps & {ref_?: any};
+
+export type Assignable<T, U> = {[k in keyof U]: k extends keyof T ? T[k] : U[k]} & Partial<T>;
diff --git a/lib/terms.ts b/lib/terms.ts
index 1a3aa82e..242c604f 100644
--- a/lib/terms.ts
+++ b/lib/terms.ts
@@ -7,5 +7,5 @@ import Term from './components/term';
 // optimization for the most common action
 // within the system
 
-const terms: Record<string, Term> = {};
+const terms: Record<string, Term | null> = {};
 export default terms;
diff --git a/lib/utils/plugins.ts b/lib/utils/plugins.ts
index 8393a5a5..c7b728cd 100644
--- a/lib/utils/plugins.ts
+++ b/lib/utils/plugins.ts
@@ -11,7 +11,19 @@ import React, {PureComponent} from 'react';
 import ReactDOM from 'react-dom';
 import Notification from '../components/notification';
 import notify from './notify';
-import {hyperPlugin, IUiReducer, ISessionReducer, ITermGroupReducer, HyperState, HyperDispatch} from '../hyper';
+import {
+  hyperPlugin,
+  IUiReducer,
+  ISessionReducer,
+  ITermGroupReducer,
+  HyperState,
+  HyperDispatch,
+  TabProps,
+  TabsProps,
+  TermGroupOwnProps,
+  TermProps,
+  Assignable
+} from '../hyper';
 import {Middleware} from 'redux';
 import {ObjectTypedKeys} from './object';
 
@@ -402,19 +414,23 @@ function getProps(name: keyof typeof propsDecorators, props: any, ...fnArgs: any
   return props_ || props;
 }
 
-export function getTermGroupProps(uid: string, parentProps: any, props: any) {
+export function getTermGroupProps<T extends Assignable<TermGroupOwnProps, T>>(
+  uid: string,
+  parentProps: any,
+  props: T
+): T {
   return getProps('getTermGroupProps', props, uid, parentProps);
 }
 
-export function getTermProps(uid: string, parentProps: any, props: any) {
+export function getTermProps<T extends Assignable<TermProps, T>>(uid: string, parentProps: any, props: T): T {
   return getProps('getTermProps', props, uid, parentProps);
 }
 
-export function getTabsProps(parentProps: any, props: any) {
+export function getTabsProps<T extends Assignable<TabsProps, T>>(parentProps: any, props: T): T {
   return getProps('getTabsProps', props, parentProps);
 }
 
-export function getTabProps(tab: any, parentProps: any, props: any) {
+export function getTabProps<T extends Assignable<TabProps, T>>(tab: any, parentProps: any, props: T): T {
   return getProps('getTabProps', props, tab, parentProps);
 }
 
diff --git a/package.json b/package.json
index b254fd0a..c9ff0222 100644
--- a/package.json
+++ b/package.json
@@ -116,6 +116,7 @@
     "prettier": "1.19.1",
     "proxyquire": "2.1.3",
     "redux-devtools-extension": "2.13.8",
+    "resize-observer-polyfill": "1.5.1",
     "spectron": "10.0.1",
     "style-loader": "1.1.3",
     "terser": "4.6.6",
diff --git a/yarn.lock b/yarn.lock
index 57082850..7f94e957 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -7049,6 +7049,11 @@ reselect@4.0.0:
   resolved "https://registry.yarnpkg.com/reselect/-/reselect-4.0.0.tgz#f2529830e5d3d0e021408b246a206ef4ea4437f7"
   integrity sha512-qUgANli03jjAyGlnbYVAV5vvnOmJnODyABz51RdBN7M4WaVu8mecZWgyQNkG8Yqe3KRGRt0l4K4B3XVEULC4CA==
 
+resize-observer-polyfill@1.5.1:
+  version "1.5.1"
+  resolved "https://registry.yarnpkg.com/resize-observer-polyfill/-/resize-observer-polyfill-1.5.1.tgz#0e9020dd3d21024458d4ebd27e23e40269810464"
+  integrity sha512-LwZrotdHOo12nQuZlHEmtuXdqGoOD0OhaxopaNFxWzInpEgaLWoVuAMbTzixuosCx2nEG58ngzW3vxdWoxIgdg==
+
 resolve-cwd@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/resolve-cwd/-/resolve-cwd-2.0.0.tgz#00a9f7387556e27038eae232caa372a6a59b665a"