[v4] docs: add pre-release banner, update version links (#4636)

packages/docs-app/src/blueprint.md

@@ -7,7 +7,7 @@ It is optimized for building complex data-dense interfaces for desktop applicati
 @reactDocs Welcome
 
 <div class="@ns-callout @ns-intent-primary @ns-icon-star">
-<h4 class="@ns-heading">Blueprint v4 is currently in beta release</h4>
+<h4 class="@ns-heading">Blueprint v4 is currently in pre-release</h4>
 
 [Check out the new features and migration guides to upgrade from v3.x &rarr;](https://github.com/palantir/blueprint/wiki/Blueprint-4.0)
 

packages/docs-app/src/components/blueprintDocs.tsx

@@ -20,7 +20,7 @@ import React from "react";
 
 import { AnchorButton, Classes, HotkeysProvider, Tag } from "@blueprintjs/core";
 import { DocsCompleteData } from "@blueprintjs/docs-data";
-import { Documentation, DocumentationProps, NavMenuItemProps, NavMenuItem } from "@blueprintjs/docs-theme";
+import { Banner, Documentation, DocumentationProps, NavMenuItemProps, NavMenuItem } from "@blueprintjs/docs-theme";
 
 import { NavHeader } from "./navHeader";
 import { NavIcon } from "./navIcons";
@@ -62,6 +62,12 @@ export class BlueprintDocs extends React.Component<BlueprintDocsProps, { themeNa
     public state = { themeName: getTheme() };
 
     public render() {
+        const banner = (
+            <Banner href="https://blueprintjs.com/docs/">
+                This is a pre-release version of Blueprint v4.x. Click here to view the docs for the latest stable
+                release (v3.x) &rarr;
+            </Banner>
+        );
         const footer = (
             <small className={classNames("docs-copyright", Classes.TEXT_MUTED)}>
                 &copy; {new Date().getFullYear()}
@@ -86,6 +92,7 @@ export class BlueprintDocs extends React.Component<BlueprintDocsProps, { themeNa
                 <Documentation
                     {...this.props}
                     className={this.state.themeName}
+                    banner={banner}
                     footer={footer}
                     header={header}
                     navigatorExclude={isNavSection}

packages/docs-app/src/components/navHeader.tsx

@@ -17,7 +17,7 @@
 import { INpmPackage } from "@documentalist/client";
 import React from "react";
 
-import { Classes, HotkeysTarget, Menu, MenuItem, NavbarHeading, Popover, Tag } from "@blueprintjs/core";
+import { Classes, HotkeysTarget, Intent, Menu, MenuItem, NavbarHeading, Popover, Tag } from "@blueprintjs/core";
 import { NavButton } from "@blueprintjs/docs-theme";
 
 import { Logo } from "./logo";
@@ -85,7 +85,21 @@ export class NavHeader extends React.PureComponent<NavHeaderProps> {
         ];
         const releaseItems = versions
             .filter(v => +major(v) > 0)
-            .map(v => <MenuItem href={v === current ? "/docs" : `/docs/versions/${major(v)}`} key={v} text={v} />);
+            .map(v => {
+                let href;
+                let intent: Intent | undefined;
+                // pre-release versions are not served as the default docs, they are inside the /versions/ folder
+                if (this.props.useNextVersion) {
+                    const isLatestStableMajor = +major(v) === +major(current) - 1;
+                    href = isLatestStableMajor ? "/docs" : `/docs/versions/${major(v)}`;
+                    if (isLatestStableMajor) {
+                        intent = "primary";
+                    }
+                } else {
+                    href = v === current ? "/docs" : `/docs/versions/${major(v)}`;
+                }
+                return <MenuItem href={href} intent={intent} key={v} text={v} />;
+            });
         return (
             <Popover content={<Menu className="docs-version-list">{releaseItems}</Menu>} placement="bottom">
                 <Tag interactive={true} minimal={true} round={true} rightIcon="caret-down">