Extract shared SectionHeader and FormFooter components (ticket 087)

Params/Metrics/Alerts/Dashboards each hand-assembled the same collapsible-
section header wiring (role/tabIndex/aria-expanded/onClick/onKeyDown around
CollapseToggle+HelpIcon+PopOutButton), and Dashboards duplicated it a second
time for its no-active-profile branch. Params/Metrics/Alerts also duplicated
the declare/edit form footer (editing banner, submit label toggle, Cancel
button). Added SectionHeader and FormFooter to CollapsibleSection.tsx and
adopted them at all five call sites; pure extraction, no behavior change.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TeyhRfMYjMditek6geDRoQ

webapp/src/components/Alerts.tsx

@@ -9,13 +9,7 @@ import {
   type AlertRule,
   type CompareOp,
 } from '../lib/api'
-import {
-  CollapseToggle,
-  handleSectionHeaderKeyDown,
-  sectionHeaderInteractiveClassName,
-  sectionHeaderLeftClassName,
-  useSectionCollapsed,
-} from './CollapsibleSection'
+import { FormFooter, SectionHeader, useSectionCollapsed } from './CollapsibleSection'
 import { HelpIcon } from './HelpIcon'
 import { RegexHelpIcon } from './RegexHelpIcon'
 import { queryInputClassName } from './FilterBar'
@@ -238,22 +232,7 @@ export function Alerts() {
 
   return (
     <div className="border-b border-border text-sm">
-      <div
-        className={sectionHeaderInteractiveClassName}
-        role="button"
-        tabIndex={0}
-        aria-expanded={!collapsed}
-        onClick={() => setCollapsed(!collapsed)}
-        onKeyDown={handleSectionHeaderKeyDown(() => setCollapsed(!collapsed))}
-      >
-        <div className={sectionHeaderLeftClassName}>
-          Alerts
-          <HelpIcon sectionId="alerts" label="Help: Alerts" />
-        </div>
-        <div className="flex items-center gap-1.5">
-          <CollapseToggle collapsed={collapsed} />
-        </div>
-      </div>
+      <SectionHeader title="Alerts" helpSectionId="alerts" collapsed={collapsed} onToggle={() => setCollapsed(!collapsed)} />
       <div hidden={collapsed}>
         <p className="px-3 pt-3 text-xs text-text-faint">
           Every rule delivers to the ntfy sink configured in Settings.
@@ -420,20 +399,13 @@ export function Alerts() {
 
           {submitError && <div className="rounded border border-danger-border bg-danger-bg/50 px-2 py-1 text-xs text-danger-text">{submitError}</div>}
 
-          <div className="flex gap-2">
-            <button
-              type="submit"
-              disabled={submitting}
-              className="rounded border border-border-soft px-3 py-1 text-sm text-text-secondary hover:bg-surface-2 disabled:opacity-50"
-            >
-              {submitting ? 'Saving…' : editingId ? 'Save rule' : 'Create rule'}
-            </button>
-            {editingId && (
-              <button type="button" onClick={startCreate} className="rounded border border-border-soft px-3 py-1 text-sm text-text-secondary hover:bg-surface-2">
-                Cancel
-              </button>
-            )}
-          </div>
+          <FormFooter
+            editing={editingId !== null}
+            submitting={submitting}
+            idleLabel="Create rule"
+            editingLabel="Save rule"
+            onCancel={startCreate}
+          />
         </form>
 
         <div className="min-w-0 flex-1">

webapp/src/components/CollapsibleSection.tsx

@@ -1,5 +1,6 @@
 import { useState } from 'react'
 import type { TimeRange, TimeRangePresetId } from '../lib/timeRange'
+import { HelpIcon } from './HelpIcon'
 
 /// Shared look for a primary section's title bar: shaded so it reads as a
 /// distinct band rather than blending into the section body below it.
@@ -95,6 +96,100 @@ export function handleSectionHeaderKeyDown(onToggle: () => void) {
   }
 }
 
+/// The header row every settings panel (Params/Metrics/Alerts/Dashboards) opens with: a click/keyboard-toggleable
+/// title bar pairing a title + `HelpIcon` on the left with `CollapseToggle` (and, for panels with a standalone
+/// popped-out view, a `PopOutButton`) on the right. Assembles `sectionHeaderInteractiveClassName` /
+/// `handleSectionHeaderKeyDown` / `sectionHeaderLeftClassName` so callers don't each re-wire the same
+/// `role="button"`/`tabIndex`/`aria-expanded` boilerplate by hand.
+export function SectionHeader({
+  title,
+  helpSectionId,
+  helpLabel,
+  collapsed,
+  onToggle,
+  popOut,
+}: {
+  title: string
+  helpSectionId: string
+  helpLabel?: string
+  collapsed: boolean
+  onToggle: () => void
+  popOut?: React.ReactNode
+}) {
+  return (
+    <div
+      className={sectionHeaderInteractiveClassName}
+      role="button"
+      tabIndex={0}
+      aria-expanded={!collapsed}
+      onClick={onToggle}
+      onKeyDown={handleSectionHeaderKeyDown(onToggle)}
+    >
+      <div className={sectionHeaderLeftClassName}>
+        {title}
+        <HelpIcon sectionId={helpSectionId} label={helpLabel ?? `Help: ${title}`} />
+      </div>
+      <div className="flex items-center gap-1.5">
+        <CollapseToggle collapsed={collapsed} />
+        {popOut}
+      </div>
+    </div>
+  )
+}
+
+/// The declare/edit form footer shared by `Params.tsx`/`Metrics.tsx`/`Alerts.tsx`: a submit button whose label
+/// swaps between create/edit and idle/in-flight variants, plus a Cancel button that only appears while editing.
+/// Doesn't render the "Editing X" banner some callers show above this — that banner's placement relative to
+/// `submitError` differs per caller, so it stays theirs to render; this covers only the part that's identical
+/// everywhere. Label text stays a per-caller prop (e.g. "Declare param" vs "Declare metric") rather than
+/// hardcoded here, since that's the one part of this footer each panel's copy actually differs on.
+export function FormFooter({
+  editing,
+  submitting,
+  idleLabel,
+  editingLabel,
+  submittingLabel = 'Saving…',
+  editingSubmittingLabel,
+  onCancel,
+}: {
+  editing: boolean
+  submitting: boolean
+  idleLabel: string
+  editingLabel: string
+  submittingLabel?: string
+  editingSubmittingLabel?: string
+  onCancel: () => void
+}) {
+  const label = submitting
+    ? editing
+      ? (editingSubmittingLabel ?? submittingLabel)
+      : submittingLabel
+    : editing
+      ? editingLabel
+      : idleLabel
+  return (
+    <div className="flex items-center gap-2">
+      <button
+        type="submit"
+        disabled={submitting}
+        className="rounded border border-border-soft px-3 py-1 text-sm text-text-secondary hover:bg-surface-2 disabled:opacity-50"
+      >
+        {label}
+      </button>
+      {editing && (
+        <button
+          type="button"
+          onClick={onCancel}
+          disabled={submitting}
+          className="rounded border border-border-soft px-3 py-1 text-sm text-text-secondary hover:bg-surface-2 disabled:opacity-50"
+        >
+          Cancel
+        </button>
+      )}
+    </div>
+  )
+}
+
 /// The four primary sections poppable into their own tab; matches the `?section=` query param a standalone page reads.
 export type PopOutSectionId = 'log' | 'params' | 'metrics' | 'dashboards'
 

webapp/src/components/Dashboards.tsx

@@ -15,15 +15,7 @@ import {
   type PromqlSeries,
 } from '../lib/api'
 import { POLL_MS } from '../lib/polling'
-import {
-  CollapseToggle,
-  handleSectionHeaderKeyDown,
-  PopOutButton,
-  sectionHeaderInteractiveClassName,
-  sectionHeaderLeftClassName,
-  useSectionCollapsed,
-} from './CollapsibleSection'
-import { HelpIcon } from './HelpIcon'
+import { PopOutButton, SectionHeader, useSectionCollapsed } from './CollapsibleSection'
 
 const CHART_TYPES: ChartType[] = ['line', 'bar', 'pie']
 
@@ -282,23 +274,13 @@ export function Dashboards({ range, activePreset }: { range: TimeRange | null; a
   if (!activeProfile) {
     return (
       <div className="border-b border-border text-sm">
-        <div
-          className={sectionHeaderInteractiveClassName}
-          role="button"
-          tabIndex={0}
-          aria-expanded={!collapsed}
-          onClick={() => setCollapsed(!collapsed)}
-          onKeyDown={handleSectionHeaderKeyDown(() => setCollapsed(!collapsed))}
-        >
-          <div className={sectionHeaderLeftClassName}>
-            Dashboards
-            <HelpIcon sectionId="dashboards" label="Help: Dashboards" />
-          </div>
-          <div className="flex items-center gap-1.5">
-            <CollapseToggle collapsed={collapsed} />
-            <PopOutButton section="dashboards" range={range} activePreset={activePreset} />
-          </div>
-        </div>
+        <SectionHeader
+          title="Dashboards"
+          helpSectionId="dashboards"
+          collapsed={collapsed}
+          onToggle={() => setCollapsed(!collapsed)}
+          popOut={<PopOutButton section="dashboards" range={range} activePreset={activePreset} />}
+        />
         <div className="p-3 text-xs text-text-faint">
           Activate a profile (see the settings menu) to create and save dashboards.
         </div>
@@ -308,23 +290,13 @@ export function Dashboards({ range, activePreset }: { range: TimeRange | null; a
 
   return (
     <div className="border-b border-border text-sm">
-      <div
-        className={sectionHeaderInteractiveClassName}
-        role="button"
-        tabIndex={0}
-        aria-expanded={!collapsed}
-        onClick={() => setCollapsed(!collapsed)}
-        onKeyDown={handleSectionHeaderKeyDown(() => setCollapsed(!collapsed))}
-      >
-        <div className={sectionHeaderLeftClassName}>
-          Dashboards
-          <HelpIcon sectionId="dashboards" label="Help: Dashboards" />
-        </div>
-        <div className="flex items-center gap-1.5">
-          <CollapseToggle collapsed={collapsed} />
-          <PopOutButton section="dashboards" range={range} activePreset={activePreset} />
-        </div>
-      </div>
+      <SectionHeader
+        title="Dashboards"
+        helpSectionId="dashboards"
+        collapsed={collapsed}
+        onToggle={() => setCollapsed(!collapsed)}
+        popOut={<PopOutButton section="dashboards" range={range} activePreset={activePreset} />}
+      />
       {error && !collapsed && (
         <div className="mx-3 mt-3 rounded border border-danger-border bg-danger-bg/50 px-2 py-1 text-xs text-danger-text">{error}</div>
       )}

webapp/src/components/Metrics.tsx

@@ -13,15 +13,7 @@ import {
   type MetricDeclaration,
   type ParamDeclaration,
 } from '../lib/api'
-import {
-  CollapseToggle,
-  handleSectionHeaderKeyDown,
-  PopOutButton,
-  sectionHeaderInteractiveClassName,
-  sectionHeaderLeftClassName,
-  useSectionCollapsed,
-} from './CollapsibleSection'
-import { HelpIcon } from './HelpIcon'
+import { FormFooter, PopOutButton, SectionHeader, useSectionCollapsed } from './CollapsibleSection'
 import { RegexHelpIcon } from './RegexHelpIcon'
 
 // One row in the labels -> occurrence count table; `values` keeps the raw points for the sparkline rendering.
@@ -207,23 +199,13 @@ export function Metrics({ range, activePreset }: { range: TimeRange | null; acti
 
   return (
     <div className="border-b border-border text-sm">
-      <div
-        className={sectionHeaderInteractiveClassName}
-        role="button"
-        tabIndex={0}
-        aria-expanded={!collapsed}
-        onClick={() => setCollapsed(!collapsed)}
-        onKeyDown={handleSectionHeaderKeyDown(() => setCollapsed(!collapsed))}
-      >
-        <div className={sectionHeaderLeftClassName}>
-          Metrics
-          <HelpIcon sectionId="metrics" label="Help: Metrics" />
-        </div>
-        <div className="flex items-center gap-1.5">
-          <CollapseToggle collapsed={collapsed} />
-          <PopOutButton section="metrics" range={range} activePreset={activePreset} />
-        </div>
-      </div>
+      <SectionHeader
+        title="Metrics"
+        helpSectionId="metrics"
+        collapsed={collapsed}
+        onToggle={() => setCollapsed(!collapsed)}
+        popOut={<PopOutButton section="metrics" range={range} activePreset={activePreset} />}
+      />
       <div className="flex gap-4 p-3" hidden={collapsed}>
         <form onSubmit={handleSubmit} className="w-80 shrink-0 space-y-2">
           <div>
@@ -300,25 +282,15 @@ export function Metrics({ range, activePreset }: { range: TimeRange | null; acti
             </div>
           )}
           {submitError && <div className="rounded border border-danger-border bg-danger-bg/50 px-2 py-1 text-xs text-danger-text">{submitError}</div>}
-          <div className="flex items-center gap-2">
-            <button
-              type="submit"
-              disabled={submitting}
-              className="rounded border border-border-soft px-3 py-1 text-sm text-text-secondary hover:bg-surface-2 disabled:opacity-50"
-            >
-              {submitting ? (editingName ? 'Saving…' : 'Declaring…') : editingName ? 'Save changes' : 'Declare metric'}
-            </button>
-            {editingName && (
-              <button
-                type="button"
-                onClick={resetForm}
-                disabled={submitting}
-                className="rounded border border-border-soft px-3 py-1 text-sm text-text-secondary hover:bg-surface-2 disabled:opacity-50"
-              >
-                Cancel
-              </button>
-            )}
-          </div>
+          <FormFooter
+            editing={editingName !== null}
+            submitting={submitting}
+            idleLabel="Declare metric"
+            editingLabel="Save changes"
+            submittingLabel="Declaring…"
+            editingSubmittingLabel="Saving…"
+            onCancel={resetForm}
+          />
         </form>
 
         <div className="min-w-0 flex-1">

webapp/src/components/Params.tsx

@@ -1,14 +1,6 @@
 import { useMemo, useState } from 'react'
 import { ApiError, clearParams, declareParam, type ParamDeclaration } from '../lib/api'
-import {
-  CollapseToggle,
-  handleSectionHeaderKeyDown,
-  PopOutButton,
-  sectionHeaderInteractiveClassName,
-  sectionHeaderLeftClassName,
-  useSectionCollapsed,
-} from './CollapsibleSection'
-import { HelpIcon } from './HelpIcon'
+import { FormFooter, PopOutButton, SectionHeader, useSectionCollapsed } from './CollapsibleSection'
 import { RegexHelpIcon } from './RegexHelpIcon'
 
 const EMPTY_KIND: ParamDeclaration['kind'] = 'string'
@@ -155,23 +147,13 @@ export function Params({ params, onDeclared }: { params: ParamDeclaration[]; onD
 
   return (
     <div className="border-b border-border text-sm">
-      <div
-        className={sectionHeaderInteractiveClassName}
-        role="button"
-        tabIndex={0}
-        aria-expanded={!collapsed}
-        onClick={() => setCollapsed(!collapsed)}
-        onKeyDown={handleSectionHeaderKeyDown(() => setCollapsed(!collapsed))}
-      >
-        <div className={sectionHeaderLeftClassName}>
-          Params
-          <HelpIcon sectionId="parameters" label="Help: Params" />
-        </div>
-        <div className="flex items-center gap-1.5">
-          <CollapseToggle collapsed={collapsed} />
-          <PopOutButton section="params" />
-        </div>
-      </div>
+      <SectionHeader
+        title="Params"
+        helpSectionId="parameters"
+        collapsed={collapsed}
+        onToggle={() => setCollapsed(!collapsed)}
+        popOut={<PopOutButton section="params" />}
+      />
       <div className="flex gap-4 p-3" hidden={collapsed}>
         <form onSubmit={handleSubmit} className="w-80 shrink-0 space-y-2">
           <div>
@@ -276,25 +258,15 @@ export function Params({ params, onDeclared }: { params: ParamDeclaration[]; onD
             </div>
           )}
           {submitError && <div className="rounded border border-danger-border bg-danger-bg/50 px-2 py-1 text-xs text-danger-text">{submitError}</div>}
-          <div className="flex items-center gap-2">
-            <button
-              type="submit"
-              disabled={submitting}
-              className="rounded border border-border-soft px-3 py-1 text-sm text-text-secondary hover:bg-surface-2 disabled:opacity-50"
-            >
-              {submitting ? (editingName ? 'Saving…' : 'Declaring…') : editingName ? 'Save changes' : 'Declare param'}
-            </button>
-            {editingName && (
-              <button
-                type="button"
-                onClick={resetForm}
-                disabled={submitting}
-                className="rounded border border-border-soft px-3 py-1 text-sm text-text-secondary hover:bg-surface-2 disabled:opacity-50"
-              >
-                Cancel
-              </button>
-            )}
-          </div>
+          <FormFooter
+            editing={editingName !== null}
+            submitting={submitting}
+            idleLabel="Declare param"
+            editingLabel="Save changes"
+            submittingLabel="Declaring…"
+            editingSubmittingLabel="Saving…"
+            onCancel={resetForm}
+          />
         </form>
 
         <div className="min-w-0 flex-1">