fix(Section): defaultIsOpen should behave as expected

packages/core/src/components/section/section.tsx

@@ -49,6 +49,9 @@ export interface SectionProps extends Props, Omit<HTMLDivProps, "title">, React.
      * This prop has no effect if `collapsible={false}`.
      */
     collapseProps?: Pick<CollapseProps, "className" | "keepChildrenMounted" | "transitionDuration"> & {
+        /**
+         * @default true
+         */
         defaultIsOpen?: boolean;
     };
 
@@ -109,7 +112,8 @@ export const Section: React.FC<SectionProps> = React.forwardRef((props, ref) =>
         title,
         ...htmlProps
     } = props;
-    const [isCollapsed, setIsCollapsed] = React.useState<boolean>(collapseProps?.defaultIsOpen ?? false);
+    // The initial useState value is negated in order to conform to the `isCollapsed` expectation.
+    const [isCollapsed, setIsCollapsed] = React.useState<boolean>(!(collapseProps?.defaultIsOpen ?? true));
     const toggleIsCollapsed = React.useCallback(() => setIsCollapsed(!isCollapsed), [isCollapsed]);
 
     const isHeaderLeftContainerVisible = title != null || icon != null || subtitle != null;

packages/core/test/index.ts

@@ -22,15 +22,15 @@ import "./common/utilsTests";
 
 // components
 import "./alert/alertTests";
-import "./breadcrumbs/breadcrumbsTests";
 import "./breadcrumbs/breadcrumbTests";
+import "./breadcrumbs/breadcrumbsTests";
 import "./buttons/buttonTests";
 import "./callout/calloutTests";
-import "./card/cardTests";
 import "./card-list/cardListTests";
+import "./card/cardTests";
 import "./collapse/collapseTests";
-import "./context-menu/contextMenuTests";
 import "./context-menu/contextMenuSingletonTests";
+import "./context-menu/contextMenuTests";
 import "./controls/controlsTests";
 import "./controls/inputGroupTests";
 import "./controls/numericInputTests";
@@ -45,8 +45,8 @@ import "./forms/textAreaTests";
 import "./hotkeys/hotkeyTests";
 import "./hotkeys/hotkeysParserTests";
 import "./hotkeys/keyComboTagTests";
-import "./html/htmlTests";
 import "./html-select/htmlSelectTests";
+import "./html/htmlTests";
 import "./icon/iconTests";
 import "./menu/menuItemTests";
 import "./menu/menuTests";
@@ -61,6 +61,7 @@ import "./popover/popperUtilTests";
 import "./portal/portalTests";
 import "./progress/progressBarTests";
 import "./resize-sensor/resizeSensorTests";
+import "./section/sectionTests";
 import "./slider/handleTests";
 import "./slider/multiSliderTests";
 import "./slider/rangeSliderTests";

packages/core/test/section/sectionTests.tsx

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2015 Palantir Technologies, Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { assert } from "chai";
+import { mount } from "enzyme";
+import * as React from "react";
+
+import { IconNames } from "@blueprintjs/icons";
+
+import { Classes, H6, Section, SectionCard } from "../../src";
+
+describe("<Section>", () => {
+    let containerElement: HTMLElement | undefined;
+
+    beforeEach(() => {
+        containerElement = document.createElement("div");
+        document.body.appendChild(containerElement);
+    });
+    afterEach(() => {
+        containerElement?.remove();
+    });
+
+    it("supports className", () => {
+        const wrapper = mount(<Section className="foo" />, {
+            attachTo: containerElement,
+        });
+        assert.isTrue(wrapper.find(`.${Classes.SECTION}`).hostNodes().exists());
+        assert.isTrue(wrapper.find(`.foo`).hostNodes().exists());
+    });
+
+    it("supports icon", () => {
+        const wrapper = mount(<Section icon={IconNames.GRAPH} title="title" />, {
+            attachTo: containerElement,
+        });
+        assert.isTrue(wrapper.find(`[data-icon="${IconNames.GRAPH}"]`).exists());
+    });
+
+    it("renders optional title element", () => {
+        const wrapper = mount(<Section title="title" />, {
+            attachTo: containerElement,
+        });
+        assert.isTrue(wrapper.find(H6).exists());
+    });
+
+    it("renders optional sub-title element", () => {
+        const wrapper = mount(<Section title="title" subtitle="subtitle" />, {
+            attachTo: containerElement,
+        });
+        assert.isTrue(wrapper.find(`.${Classes.SECTION_HEADER_SUB_TITLE}`).hostNodes().exists());
+    });
+
+    it("collapsible is open when defaultIsOpen={undefined}", () => {
+        const wrapper = mount(
+            <Section collapsible={true} collapseProps={{ defaultIsOpen: undefined }}>
+                <SectionCard>is open</SectionCard>
+            </Section>,
+            {
+                attachTo: containerElement,
+            },
+        );
+        assert.isTrue(wrapper.find(`[data-icon="${IconNames.CHEVRON_UP}"]`).exists());
+    });
+
+    it("collapsible is open when defaultIsOpen={true}", () => {
+        const wrapper = mount(
+            <Section collapsible={true} collapseProps={{ defaultIsOpen: true }}>
+                <SectionCard>is open</SectionCard>
+            </Section>,
+            {
+                attachTo: containerElement,
+            },
+        );
+        assert.isTrue(wrapper.find(`[data-icon="${IconNames.CHEVRON_UP}"]`).exists());
+    });
+
+    it("collapsible is closed when defaultIsOpen={false}", () => {
+        const wrapper = mount(
+            <Section collapsible={true} collapseProps={{ defaultIsOpen: false }}>
+                <SectionCard>is closed</SectionCard>
+            </Section>,
+            {
+                attachTo: containerElement,
+            },
+        );
+
+        assert.isTrue(wrapper.find(`[data-icon="${IconNames.CHEVRON_DOWN}"]`).exists());
+    });
+});

packages/docs-app/src/examples/core-examples/sectionExample.tsx

@@ -23,6 +23,7 @@ import {
     EditableText,
     Elevation,
     H5,
+    H6,
     Label,
     Section,
     SectionCard,
@@ -35,6 +36,7 @@ import { IconNames } from "@blueprintjs/icons";
 
 export interface SectionExampleState {
     collapsible: boolean;
+    defaultIsOpen: boolean;
     elevation: SectionElevation;
     hasDescription: boolean;
     hasIcon: boolean;
@@ -54,6 +56,7 @@ const BASIL_DESCRIPTION_TEXT = dedent`
 export class SectionExample extends React.PureComponent<ExampleProps, SectionExampleState> {
     public state: SectionExampleState = {
         collapsible: false,
+        defaultIsOpen: true,
         elevation: Elevation.ZERO,
         hasDescription: false,
         hasIcon: false,
@@ -68,6 +71,7 @@ export class SectionExample extends React.PureComponent<ExampleProps, SectionExa
     public render() {
         const {
             collapsible,
+            defaultIsOpen,
             elevation,
             hasDescription,
             hasIcon,
@@ -82,9 +86,15 @@ export class SectionExample extends React.PureComponent<ExampleProps, SectionExa
                 <H5>Section Props</H5>
                 <Switch checked={isCompact} label="Compact" onChange={this.toggleIsCompact} />
                 <Switch checked={hasIcon} label="Icon" onChange={this.toggleHasIcon} />
-                <Switch checked={hasDescription} label="Description" onChange={this.toggleHasDescription} />
+                <Switch checked={hasDescription} label="Sub-title" onChange={this.toggleHasDescription} />
                 <Switch checked={hasRightElement} label="Right element" onChange={this.toggleHasRightElement} />
                 <Switch checked={collapsible} label="Collapsible" onChange={this.toggleCollapsible} />
+                {collapsible && (
+                    <>
+                        <H6>Collapse Props</H6>
+                        <Switch checked={defaultIsOpen} label="Default is open" onChange={this.toggleDefaultIsOpen} />
+                    </>
+                )}
                 <Label>
                     Elevation
                     <Slider
@@ -134,8 +144,14 @@ export class SectionExample extends React.PureComponent<ExampleProps, SectionExa
         return (
             <Example options={options} {...this.props}>
                 <Section
+                    // A `key` is provided here to force the component to
+                    // re-mount when `defaultIsOpen` is changed, otherwise
+                    // the local state in the `Collapse` component is not
+                    // updated.
+                    key={String(defaultIsOpen)}
                     collapsible={collapsible}
                     compact={isCompact}
+                    collapseProps={{ defaultIsOpen }}
                     elevation={elevation}
                     icon={hasIcon ? IconNames.BOOK : undefined}
                     rightElement={
@@ -170,6 +186,8 @@ export class SectionExample extends React.PureComponent<ExampleProps, SectionExa
 
     private toggleCollapsible = () => this.setState({ collapsible: !this.state.collapsible });
 
+    private toggleDefaultIsOpen = () => this.setState({ defaultIsOpen: !this.state.defaultIsOpen });
+
     private togglePanelIsPadded = () => this.setState({ isPanelPadded: !this.state.isPanelPadded });
 
     private handleElevationChange = (elevation: SectionElevation) => this.setState({ elevation });