diff --git a/src/async-components/views/dialogs/eventindex/DisableEventIndexDialog.js b/src/async-components/views/dialogs/eventindex/DisableEventIndexDialog.tsx
similarity index 77%
rename from src/async-components/views/dialogs/eventindex/DisableEventIndexDialog.js
rename to src/async-components/views/dialogs/eventindex/DisableEventIndexDialog.tsx
index e1c2b7b202..4d8f5e5663 100644
--- a/src/async-components/views/dialogs/eventindex/DisableEventIndexDialog.js
+++ b/src/async-components/views/dialogs/eventindex/DisableEventIndexDialog.tsx
@@ -15,8 +15,10 @@ limitations under the License.
 */
 
 import React from 'react';
-import * as sdk from '../../../../index';
-import PropTypes from 'prop-types';
+
+import BaseDialog from "../../../../components/views/dialogs/BaseDialog";
+import Spinner from "../../../../components/views/elements/Spinner";
+import DialogButtons from "../../../../components/views/elements/DialogButtons";
 import dis from "../../../../dispatcher/dispatcher";
 import { _t } from '../../../../languageHandler';
 
@@ -24,46 +26,44 @@ import SettingsStore from "../../../../settings/SettingsStore";
 import EventIndexPeg from "../../../../indexing/EventIndexPeg";
 import { Action } from "../../../../dispatcher/actions";
 import { SettingLevel } from "../../../../settings/SettingLevel";
+interface IProps {
+    onFinished: (success: boolean) => void;
+}
+
+interface IState {
+    disabling: boolean;
+}
 
 /*
  * Allows the user to disable the Event Index.
  */
-export default class DisableEventIndexDialog extends React.Component {
-    static propTypes = {
-        onFinished: PropTypes.func.isRequired,
-    }
-
-    constructor(props) {
+export default class DisableEventIndexDialog extends React.Component<IProps, IState> {
+    constructor(props: IProps) {
         super(props);
-
         this.state = {
             disabling: false,
         };
     }
 
-    _onDisable = async () => {
+    private onDisable = async (): Promise<void> => {
         this.setState({
             disabling: true,
         });
 
         await SettingsStore.setValue('enableEventIndexing', null, SettingLevel.DEVICE, false);
         await EventIndexPeg.deleteEventIndex();
-        this.props.onFinished();
+        this.props.onFinished(true);
         dis.fire(Action.ViewUserSettings);
-    }
-
-    render() {
-        const BaseDialog = sdk.getComponent('views.dialogs.BaseDialog');
-        const Spinner = sdk.getComponent('elements.Spinner');
-        const DialogButtons = sdk.getComponent('views.elements.DialogButtons');
+    };
 
+    public render(): React.ReactNode {
         return (
             <BaseDialog onFinished={this.props.onFinished} title={_t("Are you sure?")}>
                 { _t("If disabled, messages from encrypted rooms won't appear in search results.") }
                 { this.state.disabling ? <Spinner /> : <div /> }
                 <DialogButtons
                     primaryButton={_t('Disable')}
-                    onPrimaryButtonClick={this._onDisable}
+                    onPrimaryButtonClick={this.onDisable}
                     primaryButtonClass="danger"
                     cancelButtonClass="warning"
                     onCancel={this.props.onFinished}
diff --git a/src/async-components/views/dialogs/eventindex/ManageEventIndexDialog.tsx b/src/async-components/views/dialogs/eventindex/ManageEventIndexDialog.tsx
index 20ba91f5e2..2748fda35a 100644
--- a/src/async-components/views/dialogs/eventindex/ManageEventIndexDialog.tsx
+++ b/src/async-components/views/dialogs/eventindex/ManageEventIndexDialog.tsx
@@ -134,8 +134,9 @@ export default class ManageEventIndexDialog extends React.Component<IProps, ISta
     }
 
     private onDisable = async () => {
-        Modal.createTrackedDialogAsync("Disable message search", "Disable message search",
-            import("./DisableEventIndexDialog"),
+        const DisableEventIndexDialog = (await import("./DisableEventIndexDialog")).default;
+        Modal.createTrackedDialog("Disable message search", "Disable message search",
+            DisableEventIndexDialog,
             null, null, /* priority = */ false, /* static = */ true,
         );
     };
diff --git a/src/components/views/auth/AuthBody.js b/src/components/views/auth/AuthBody.tsx
similarity index 95%
rename from src/components/views/auth/AuthBody.js
rename to src/components/views/auth/AuthBody.tsx
index abe7fd2fd3..3543a573d7 100644
--- a/src/components/views/auth/AuthBody.js
+++ b/src/components/views/auth/AuthBody.tsx
@@ -19,7 +19,7 @@ import { replaceableComponent } from "../../../utils/replaceableComponent";
 
 @replaceableComponent("views.auth.AuthBody")
 export default class AuthBody extends React.PureComponent {
-    render() {
+    public render(): React.ReactNode {
         return <div className="mx_AuthBody">
             { this.props.children }
         </div>;
diff --git a/src/components/views/auth/AuthFooter.js b/src/components/views/auth/AuthFooter.tsx
similarity index 96%
rename from src/components/views/auth/AuthFooter.js
rename to src/components/views/auth/AuthFooter.tsx
index e81d2cd969..00bced8c39 100644
--- a/src/components/views/auth/AuthFooter.js
+++ b/src/components/views/auth/AuthFooter.tsx
@@ -22,7 +22,7 @@ import { replaceableComponent } from "../../../utils/replaceableComponent";
 
 @replaceableComponent("views.auth.AuthFooter")
 export default class AuthFooter extends React.Component {
-    render() {
+    public render(): React.ReactNode {
         return (
             <div className="mx_AuthFooter">
                 <a href="https://matrix.org" target="_blank" rel="noreferrer noopener">{ _t("powered by Matrix") }</a>
diff --git a/src/components/views/auth/AuthHeader.js b/src/components/views/auth/AuthHeader.tsx
similarity index 71%
rename from src/components/views/auth/AuthHeader.js
rename to src/components/views/auth/AuthHeader.tsx
index d9bd81adcb..cab7da1468 100644
--- a/src/components/views/auth/AuthHeader.js
+++ b/src/components/views/auth/AuthHeader.tsx
@@ -16,20 +16,17 @@ limitations under the License.
 */
 
 import React from 'react';
-import PropTypes from 'prop-types';
-import * as sdk from '../../../index';
 import { replaceableComponent } from "../../../utils/replaceableComponent";
+import AuthHeaderLogo from "./AuthHeaderLogo";
+import LanguageSelector from "./LanguageSelector";
+
+interface IProps {
+    disableLanguageSelector?: boolean;
+}
 
 @replaceableComponent("views.auth.AuthHeader")
-export default class AuthHeader extends React.Component {
-    static propTypes = {
-        disableLanguageSelector: PropTypes.bool,
-    };
-
-    render() {
-        const AuthHeaderLogo = sdk.getComponent('auth.AuthHeaderLogo');
-        const LanguageSelector = sdk.getComponent('views.auth.LanguageSelector');
-
+export default class AuthHeader extends React.Component<IProps> {
+    public render(): React.ReactNode {
         return (
             <div className="mx_AuthHeader">
                 <AuthHeaderLogo />
diff --git a/src/components/views/auth/AuthHeaderLogo.js b/src/components/views/auth/AuthHeaderLogo.tsx
similarity index 95%
rename from src/components/views/auth/AuthHeaderLogo.js
rename to src/components/views/auth/AuthHeaderLogo.tsx
index 0adf18dc1c..b6724793a5 100644
--- a/src/components/views/auth/AuthHeaderLogo.js
+++ b/src/components/views/auth/AuthHeaderLogo.tsx
@@ -19,7 +19,7 @@ import { replaceableComponent } from "../../../utils/replaceableComponent";
 
 @replaceableComponent("views.auth.AuthHeaderLogo")
 export default class AuthHeaderLogo extends React.PureComponent {
-    render() {
+    public render(): React.ReactNode {
         return <div className="mx_AuthHeaderLogo">
             Matrix
         </div>;
diff --git a/src/components/views/auth/AuthPage.js b/src/components/views/auth/AuthPage.tsx
similarity index 90%
rename from src/components/views/auth/AuthPage.js
rename to src/components/views/auth/AuthPage.tsx
index 6a73b06c16..c402d5b699 100644
--- a/src/components/views/auth/AuthPage.js
+++ b/src/components/views/auth/AuthPage.tsx
@@ -17,14 +17,12 @@ limitations under the License.
 */
 
 import React from 'react';
-import * as sdk from '../../../index';
 import { replaceableComponent } from "../../../utils/replaceableComponent";
+import AuthFooter from "./AuthFooter";
 
 @replaceableComponent("views.auth.AuthPage")
 export default class AuthPage extends React.PureComponent {
-    render() {
-        const AuthFooter = sdk.getComponent('auth.AuthFooter');
-
+    public render(): React.ReactNode {
         return (
             <div className="mx_AuthPage">
                 <div className="mx_AuthPage_modal">
diff --git a/src/components/views/auth/CompleteSecurityBody.js b/src/components/views/auth/CompleteSecurityBody.tsx
similarity index 95%
rename from src/components/views/auth/CompleteSecurityBody.js
rename to src/components/views/auth/CompleteSecurityBody.tsx
index 745d7abbf2..8f6affb64e 100644
--- a/src/components/views/auth/CompleteSecurityBody.js
+++ b/src/components/views/auth/CompleteSecurityBody.tsx
@@ -19,7 +19,7 @@ import { replaceableComponent } from "../../../utils/replaceableComponent";
 
 @replaceableComponent("views.auth.CompleteSecurityBody")
 export default class CompleteSecurityBody extends React.PureComponent {
-    render() {
+    public render(): React.ReactNode {
         return <div className="mx_CompleteSecurityBody">
             { this.props.children }
         </div>;
diff --git a/src/components/views/auth/CountryDropdown.js b/src/components/views/auth/CountryDropdown.tsx
similarity index 75%
rename from src/components/views/auth/CountryDropdown.js
rename to src/components/views/auth/CountryDropdown.tsx
index cbc19e0f8d..eb5b27be9d 100644
--- a/src/components/views/auth/CountryDropdown.js
+++ b/src/components/views/auth/CountryDropdown.tsx
@@ -15,21 +15,19 @@ limitations under the License.
 */
 
 import React from 'react';
-import PropTypes from 'prop-types';
 
-import * as sdk from '../../../index';
-
-import { COUNTRIES, getEmojiFlag } from '../../../phonenumber';
+import { COUNTRIES, getEmojiFlag, PhoneNumberCountryDefinition } from '../../../phonenumber';
 import SdkConfig from "../../../SdkConfig";
 import { _t } from "../../../languageHandler";
 import { replaceableComponent } from "../../../utils/replaceableComponent";
+import Dropdown from "../elements/Dropdown";
 
 const COUNTRIES_BY_ISO2 = {};
 for (const c of COUNTRIES) {
     COUNTRIES_BY_ISO2[c.iso2] = c;
 }
 
-function countryMatchesSearchQuery(query, country) {
+function countryMatchesSearchQuery(query: string, country: PhoneNumberCountryDefinition): boolean {
     // Remove '+' if present (when searching for a prefix)
     if (query[0] === '+') {
         query = query.slice(1);
@@ -41,15 +39,26 @@ function countryMatchesSearchQuery(query, country) {
     return false;
 }
 
-@replaceableComponent("views.auth.CountryDropdown")
-export default class CountryDropdown extends React.Component {
-    constructor(props) {
-        super(props);
-        this._onSearchChange = this._onSearchChange.bind(this);
-        this._onOptionChange = this._onOptionChange.bind(this);
-        this._getShortOption = this._getShortOption.bind(this);
+interface IProps {
+    value?: string;
+    onOptionChange: (country: PhoneNumberCountryDefinition) => void;
+    isSmall: boolean; // if isSmall, show +44 in the selected value
+    showPrefix: boolean;
+    className?: string;
+    disabled?: boolean;
+}
 
-        let defaultCountry = COUNTRIES[0];
+interface IState {
+    searchQuery: string;
+    defaultCountry: PhoneNumberCountryDefinition;
+}
+
+@replaceableComponent("views.auth.CountryDropdown")
+export default class CountryDropdown extends React.Component<IProps, IState> {
+    constructor(props: IProps) {
+        super(props);
+
+        let defaultCountry: PhoneNumberCountryDefinition = COUNTRIES[0];
         const defaultCountryCode = SdkConfig.get()["defaultCountryCode"];
         if (defaultCountryCode) {
             const country = COUNTRIES.find(c => c.iso2 === defaultCountryCode.toUpperCase());
@@ -62,7 +71,7 @@ export default class CountryDropdown extends React.Component {
         };
     }
 
-    componentDidMount() {
+    public componentDidMount(): void {
         if (!this.props.value) {
             // If no value is given, we start with the default
             // country selected, but our parent component
@@ -71,21 +80,21 @@ export default class CountryDropdown extends React.Component {
         }
     }
 
-    _onSearchChange(search) {
+    private onSearchChange = (search: string): void => {
         this.setState({
             searchQuery: search,
         });
-    }
+    };
 
-    _onOptionChange(iso2) {
+    private onOptionChange = (iso2: string): void => {
         this.props.onOptionChange(COUNTRIES_BY_ISO2[iso2]);
-    }
+    };
 
-    _flagImgForIso2(iso2) {
+    private flagImgForIso2(iso2: string): React.ReactNode {
         return <div className="mx_Dropdown_option_emoji">{ getEmojiFlag(iso2) }</div>;
     }
 
-    _getShortOption(iso2) {
+    private getShortOption = (iso2: string): React.ReactNode => {
         if (!this.props.isSmall) {
             return undefined;
         }
@@ -94,14 +103,12 @@ export default class CountryDropdown extends React.Component {
             countryPrefix = '+' + COUNTRIES_BY_ISO2[iso2].prefix;
         }
         return <span className="mx_CountryDropdown_shortOption">
-            { this._flagImgForIso2(iso2) }
+            { this.flagImgForIso2(iso2) }
             { countryPrefix }
         </span>;
-    }
-
-    render() {
-        const Dropdown = sdk.getComponent('elements.Dropdown');
+    };
 
+    public render(): React.ReactNode {
         let displayedCountries;
         if (this.state.searchQuery) {
             displayedCountries = COUNTRIES.filter(
@@ -124,7 +131,7 @@ export default class CountryDropdown extends React.Component {
 
         const options = displayedCountries.map((country) => {
             return <div className="mx_CountryDropdown_option" key={country.iso2}>
-                { this._flagImgForIso2(country.iso2) }
+                { this.flagImgForIso2(country.iso2) }
                 { _t(country.name) } (+{ country.prefix })
             </div>;
         });
@@ -136,10 +143,10 @@ export default class CountryDropdown extends React.Component {
         return <Dropdown
             id="mx_CountryDropdown"
             className={this.props.className + " mx_CountryDropdown"}
-            onOptionChange={this._onOptionChange}
-            onSearchChange={this._onSearchChange}
+            onOptionChange={this.onOptionChange}
+            onSearchChange={this.onSearchChange}
             menuWidth={298}
-            getShortOption={this._getShortOption}
+            getShortOption={this.getShortOption}
             value={value}
             searchEnabled={true}
             disabled={this.props.disabled}
@@ -149,13 +156,3 @@ export default class CountryDropdown extends React.Component {
         </Dropdown>;
     }
 }
-
-CountryDropdown.propTypes = {
-    className: PropTypes.string,
-    isSmall: PropTypes.bool,
-    // if isSmall, show +44 in the selected value
-    showPrefix: PropTypes.bool,
-    onOptionChange: PropTypes.func.isRequired,
-    value: PropTypes.string,
-    disabled: PropTypes.bool,
-};
diff --git a/src/components/views/auth/LanguageSelector.js b/src/components/views/auth/LanguageSelector.tsx
similarity index 85%
rename from src/components/views/auth/LanguageSelector.js
rename to src/components/views/auth/LanguageSelector.tsx
index 88293310e7..c26b4797f3 100644
--- a/src/components/views/auth/LanguageSelector.js
+++ b/src/components/views/auth/LanguageSelector.tsx
@@ -18,21 +18,23 @@ import SdkConfig from "../../../SdkConfig";
 import { getCurrentLanguage } from "../../../languageHandler";
 import SettingsStore from "../../../settings/SettingsStore";
 import PlatformPeg from "../../../PlatformPeg";
-import * as sdk from '../../../index';
 import React from 'react';
 import { SettingLevel } from "../../../settings/SettingLevel";
+import LanguageDropdown from "../elements/LanguageDropdown";
 
-function onChange(newLang) {
+function onChange(newLang: string): void {
     if (getCurrentLanguage() !== newLang) {
         SettingsStore.setValue("language", null, SettingLevel.DEVICE, newLang);
         PlatformPeg.get().reload();
     }
 }
 
-export default function LanguageSelector({ disabled }) {
-    if (SdkConfig.get()['disable_login_language_selector']) return <div />;
+interface IProps {
+    disabled?: boolean;
+}
 
-    const LanguageDropdown = sdk.getComponent('views.elements.LanguageDropdown');
+export default function LanguageSelector({ disabled }: IProps): JSX.Element {
+    if (SdkConfig.get()['disable_login_language_selector']) return <div />;
     return <LanguageDropdown
         className="mx_AuthBody_language"
         onOptionChange={onChange}
diff --git a/src/components/views/auth/Welcome.js b/src/components/views/auth/Welcome.tsx
similarity index 83%
rename from src/components/views/auth/Welcome.js
rename to src/components/views/auth/Welcome.tsx
index e3f7a601f2..0e12025fbd 100644
--- a/src/components/views/auth/Welcome.js
+++ b/src/components/views/auth/Welcome.tsx
@@ -17,7 +17,7 @@ limitations under the License.
 import React from 'react';
 import classNames from "classnames";
 
-import * as sdk from '../../../index';
+import * as sdk from "../../../index";
 import SdkConfig from '../../../SdkConfig';
 import AuthPage from "./AuthPage";
 import { _td } from "../../../languageHandler";
@@ -25,21 +25,26 @@ import SettingsStore from "../../../settings/SettingsStore";
 import { UIFeature } from "../../../settings/UIFeature";
 import CountlyAnalytics from "../../../CountlyAnalytics";
 import { replaceableComponent } from "../../../utils/replaceableComponent";
+import LanguageSelector from "./LanguageSelector";
 
 // translatable strings for Welcome pages
 _td("Sign in with SSO");
 
+interface IProps {
+
+}
+
 @replaceableComponent("views.auth.Welcome")
-export default class Welcome extends React.PureComponent {
-    constructor(props) {
+export default class Welcome extends React.PureComponent<IProps> {
+    constructor(props: IProps) {
         super(props);
 
         CountlyAnalytics.instance.track("onboarding_welcome");
     }
 
-    render() {
-        const EmbeddedPage = sdk.getComponent('structures.EmbeddedPage');
-        const LanguageSelector = sdk.getComponent('auth.LanguageSelector');
+    public render(): React.ReactNode {
+        // FIXME: Using an import will result in wrench-element-tests failures
+        const EmbeddedPage = sdk.getComponent("structures.EmbeddedPage");
 
         const pagesConfig = SdkConfig.get().embeddedPages;
         let pageUrl = null;
diff --git a/src/phonenumber.ts b/src/phonenumber.ts
index ea008cf2f0..51d12babed 100644
--- a/src/phonenumber.ts
+++ b/src/phonenumber.ts
@@ -42,7 +42,13 @@ export const getEmojiFlag = (countryCode: string) => {
     return String.fromCodePoint(...countryCode.split('').map(l => UNICODE_BASE + l.charCodeAt(0)));
 };
 
-export const COUNTRIES = [
+export interface PhoneNumberCountryDefinition {
+    iso2: string;
+    name: string;
+    prefix: string;
+}
+
+export const COUNTRIES: PhoneNumberCountryDefinition[] = [
     {
         "iso2": "GB",
         "name": _td("United Kingdom"),