Add back strict null checks to react-shared package and fix issues

packages/react-shared/src/ts/components/markdown_section.tsx

@@ -19,6 +19,12 @@ export interface MarkdownSectionProps {
     githubLink?: string;
 }
 
+interface DefaultMarkdownSectionProps {
+  headerSize: HeaderSizes;
+}
+
+type PropsWithDefaults = MarkdownSectionProps & DefaultMarkdownSectionProps;
+
 export interface MarkdownSectionState {
     shouldShowAnchor: boolean;
 }
@@ -34,7 +40,8 @@ export class MarkdownSection extends React.Component<MarkdownSectionProps, Markd
         };
     }
     public render() {
-        const sectionName = this.props.sectionName;
+        const { sectionName, markdownContent, headerSize, githubLink } = this.props as PropsWithDefaults;
+
         const id = utils.getIdFromName(sectionName);
         return (
             <div
@@ -47,7 +54,7 @@ export class MarkdownSection extends React.Component<MarkdownSectionProps, Markd
                         <div className="col lg-col-8 md-col-8 sm-col-12">
                             <span style={{ textTransform: 'capitalize', color: colors.grey700 }}>
                                 <AnchorTitle
-                                    headerSize={this.props.headerSize}
+                                    headerSize={headerSize}
                                     title={sectionName}
                                     id={id}
                                     shouldShowAnchor={this.state.shouldShowAnchor}
@@ -55,9 +62,9 @@ export class MarkdownSection extends React.Component<MarkdownSectionProps, Markd
                             </span>
                         </div>
                         <div className="col col-4 sm-hide xs-hide right-align pr3" style={{ height: 28 }}>
-                            {!_.isUndefined(this.props.githubLink) && (
+                            {!_.isUndefined(githubLink) && (
                                 <a
-                                    href={this.props.githubLink}
+                                    href={githubLink}
                                     target="_blank"
                                     style={{ color: colors.linkBlue, textDecoration: 'none', lineHeight: 2.1 }}
                                 >
@@ -68,7 +75,7 @@ export class MarkdownSection extends React.Component<MarkdownSectionProps, Markd
                     </div>
                     <hr style={{ border: `1px solid ${colors.lightestGrey}` }} />
                     <ReactMarkdown
-                        source={this.props.markdownContent}
+                        source={markdownContent}
                         escapeHtml={false}
                         renderers={{
                             code: MarkdownCodeBlock,

packages/react-shared/src/ts/components/nested_sidebar_menu.tsx

@@ -65,7 +65,8 @@ export class NestedSidebarMenu extends React.Component<NestedSidebarMenuProps, N
             <div>
                 {this.props.sidebarHeader}
                 {!_.isUndefined(this.props.versions) &&
-                    !_.isUndefined(this.props.selectedVersion) && (
+                    !_.isUndefined(this.props.selectedVersion) &&
+                    !_.isUndefined(this.props.onVersionSelected) && (
                         <div style={{ maxWidth: maxWidthWithScrollbar }}>
                             <VersionDropDown
                                 selectedVersion={this.props.selectedVersion}
@@ -150,6 +151,8 @@ export class NestedSidebarMenu extends React.Component<NestedSidebarMenuProps, N
     private _onMenuItemClick(name: string): void {
         const id = utils.getIdFromName(name);
         utils.setUrlHash(id);
-        this.props.onMenuItemClick();
+        if (!_.isUndefined(this.props.onMenuItemClick)) {
+            this.props.onMenuItemClick();
+        }
     }
 }

packages/react-shared/src/ts/components/section_header.tsx

@@ -12,6 +12,12 @@ export interface SectionHeaderProps {
     headerSize?: HeaderSizes;
 }
 
+interface DefaultSectionHeaderProps {
+  headerSize: HeaderSizes;
+}
+
+type PropsWithDefaults = SectionHeaderProps & DefaultSectionHeaderProps;
+
 export interface SectionHeaderState {
     shouldShowAnchor: boolean;
 }
@@ -27,8 +33,10 @@ export class SectionHeader extends React.Component<SectionHeaderProps, SectionHe
         };
     }
     public render() {
-        const sectionName = this.props.sectionName.replace(/-/g, ' ');
-        const id = utils.getIdFromName(sectionName);
+        const { sectionName, headerSize } = this.props as PropsWithDefaults;
+
+        const finalSectionName = this.props.sectionName.replace(/-/g, ' ');
+        const id = utils.getIdFromName(finalSectionName);
         return (
             <div
                 onMouseOver={this._setAnchorVisibility.bind(this, true)}
@@ -36,7 +44,7 @@ export class SectionHeader extends React.Component<SectionHeaderProps, SectionHe
             >
                 <ScrollElement name={id}>
                     <AnchorTitle
-                        headerSize={this.props.headerSize}
+                        headerSize={headerSize}
                         title={
                             <span
                                 style={{
@@ -47,7 +55,7 @@ export class SectionHeader extends React.Component<SectionHeaderProps, SectionHe
                                     fontSize: 27,
                                 }}
                             >
-                                {sectionName}
+                                {finalSectionName}
                             </span>
                         }
                         id={id}

packages/react-shared/src/ts/utils/utils.ts

@@ -30,7 +30,7 @@ export const utils = {
         const id = name.replace(/ /g, '-');
         return id;
     },
-    getEtherScanLinkIfExists(addressOrTxHash: string, networkId: number, suffix: EtherscanLinkSuffixes): string {
+    getEtherScanLinkIfExists(addressOrTxHash: string, networkId: number, suffix: EtherscanLinkSuffixes): string|undefined {
         const networkName = constants.NETWORK_NAME_BY_ID[networkId];
         if (_.isUndefined(networkName)) {
             return undefined;