Add conditional form schema

src/components/ha-form/ha-form-conditional.ts

@@ -0,0 +1,74 @@
+import {
+  css,
+  CSSResultGroup,
+  html,
+  LitElement,
+  nothing,
+  PropertyValues,
+} from "lit";
+import { customElement, property } from "lit/decorators";
+import type { HomeAssistant } from "../../types";
+import "./ha-form";
+import type {
+  HaFormDataContainer,
+  HaFormElement,
+  HaFormConditionalSchema,
+  HaFormSchema,
+} from "./types";
+
+@customElement("ha-form-conditional")
+export class HaFormConditional extends LitElement implements HaFormElement {
+  @property({ attribute: false }) public hass!: HomeAssistant;
+
+  @property({ attribute: false }) public data!: HaFormDataContainer;
+
+  @property({ attribute: false }) public schema!: HaFormConditionalSchema;
+
+  @property({ type: Boolean }) public disabled = false;
+
+  @property() public computeLabel?: (
+    schema: HaFormSchema,
+    data?: HaFormDataContainer
+  ) => string;
+
+  @property() public computeHelper?: (schema: HaFormSchema) => string;
+
+  protected updated(changedProps: PropertyValues): void {
+    if (changedProps.has("schema") || changedProps.has("data")) {
+      this.toggleAttribute("hidden", !this.schema.condition(this.data));
+    }
+  }
+
+  protected render() {
+    if (!this.schema.condition(this.data)) {
+      return nothing;
+    }
+    return html`
+      <ha-form
+        .hass=${this.hass}
+        .data=${this.data}
+        .schema=${this.schema.schema}
+        .disabled=${this.disabled}
+        .computeLabel=${this.computeLabel}
+        .computeHelper=${this.computeHelper}
+      ></ha-form>
+    `;
+  }
+
+  static get styles(): CSSResultGroup {
+    return css`
+      :host([hidden]) {
+        display: none !important;
+      }
+      :host ha-form {
+        display: block;
+      }
+    `;
+  }
+}
+
+declare global {
+  interface HTMLElementTagNameMap {
+    "ha-form-conditional": HaFormConditional;
+  }
+}

src/components/ha-form/ha-form.ts

@@ -21,6 +21,7 @@ const LOAD_ELEMENTS = {
   float: () => import("./ha-form-float"),
   grid: () => import("./ha-form-grid"),
   expandable: () => import("./ha-form-expandable"),
+  conditional: () => import("./ha-form-conditional"),
   integer: () => import("./ha-form-integer"),
   multi_select: () => import("./ha-form-multi_select"),
   positive_time_period_dict: () =>
@@ -189,12 +190,13 @@ export class HaForm extends LitElement implements HaFormElement {
 
   static get styles(): CSSResultGroup {
     return css`
+      .root {
+        display: grid;
+        row-gap: 24px;
+      }
       .root > * {
         display: block;
       }
-      .root > *:not([own-margin]):not(:last-child) {
-        margin-bottom: 24px;
-      }
       ha-alert[own-margin] {
         margin-bottom: 4px;
       }

src/components/ha-form/types.ts

@@ -13,7 +13,8 @@ export type HaFormSchema =
   | HaFormTimeSchema
   | HaFormSelector
   | HaFormGridSchema
-  | HaFormExpandableSchema;
+  | HaFormExpandableSchema
+  | HaFormConditionalSchema;
 
 export interface HaFormBaseSchema {
   name: string;
@@ -47,6 +48,13 @@ export interface HaFormExpandableSchema extends HaFormBaseSchema {
   schema: readonly HaFormSchema[];
 }
 
+export interface HaFormConditionalSchema extends HaFormBaseSchema {
+  type: "conditional";
+  name: "";
+  condition: (data: HaFormDataContainer) => boolean;
+  schema: readonly HaFormSchema[];
+}
+
 export interface HaFormSelector extends HaFormBaseSchema {
   type?: never;
   selector: Selector;
@@ -99,7 +107,10 @@ export interface HaFormTimeSchema extends HaFormBaseSchema {
 export type SchemaUnion<
   SchemaArray extends readonly HaFormSchema[],
   Schema = SchemaArray[number]
-> = Schema extends HaFormGridSchema | HaFormExpandableSchema
+> = Schema extends
+  | HaFormGridSchema
+  | HaFormExpandableSchema
+  | HaFormConditionalSchema
   ? SchemaUnion<Schema["schema"]>
   : Schema;
 

src/panels/lovelace/editor/config-elements/hui-gauge-card-editor.ts

@@ -1,6 +1,5 @@
 import { html, LitElement, nothing } from "lit";
 import { customElement, property, state } from "lit/decorators";
-import memoizeOne from "memoize-one";
 import {
   array,
   assert,
@@ -13,7 +12,10 @@ import {
 } from "superstruct";
 import { fireEvent } from "../../../../common/dom/fire_event";
 import "../../../../components/ha-form/ha-form";
-import type { SchemaUnion } from "../../../../components/ha-form/types";
+import type {
+  HaFormSchema,
+  SchemaUnion,
+} from "../../../../components/ha-form/types";
 import type { HomeAssistant } from "../../../../types";
 import type { GaugeCardConfig } from "../../cards/types";
 import type { LovelaceCardEditor } from "../../types";
@@ -41,23 +43,7 @@ const cardConfigStruct = assign(
   })
 );
 
-@customElement("hui-gauge-card-editor")
-export class HuiGaugeCardEditor
-  extends LitElement
-  implements LovelaceCardEditor
-{
-  @property({ attribute: false }) public hass?: HomeAssistant;
-
-  @state() private _config?: GaugeCardConfig;
-
-  public setConfig(config: GaugeCardConfig): void {
-    assert(config, cardConfigStruct);
-    this._config = config;
-  }
-
-  private _schema = memoizeOne(
-    (showSeverity: boolean) =>
-      [
+const SCHEMA = [
   {
     name: "entity",
     selector: {
@@ -99,8 +85,11 @@ export class HuiGaugeCardEditor
       { name: "show_severity", selector: { boolean: {} } },
     ],
   },
-        ...(showSeverity
-          ? ([
+  {
+    name: "",
+    type: "conditional",
+    condition: (data) => !!data.show_severity,
+    schema: [
       {
         name: "severity",
         type: "grid",
@@ -119,17 +108,29 @@ export class HuiGaugeCardEditor
           },
         ],
       },
-            ] as const)
-          : []),
-      ] as const
-  );
+    ],
+  },
+] as const satisfies readonly HaFormSchema[];
+
+@customElement("hui-gauge-card-editor")
+export class HuiGaugeCardEditor
+  extends LitElement
+  implements LovelaceCardEditor
+{
+  @property({ attribute: false }) public hass?: HomeAssistant;
+
+  @state() private _config?: GaugeCardConfig;
+
+  public setConfig(config: GaugeCardConfig): void {
+    assert(config, cardConfigStruct);
+    this._config = config;
+  }
 
   protected render() {
     if (!this.hass || !this._config) {
       return nothing;
     }
 
-    const schema = this._schema(this._config!.severity !== undefined);
     const data = {
       show_severity: this._config!.severity !== undefined,
       ...this._config,
@@ -139,7 +140,7 @@ export class HuiGaugeCardEditor
       <ha-form
         .hass=${this.hass}
         .data=${data}
-        .schema=${schema}
+        .schema=${SCHEMA}
         .computeLabel=${this._computeLabelCallback}
         @value-changed=${this._valueChanged}
       ></ha-form>
@@ -153,7 +154,7 @@ export class HuiGaugeCardEditor
       config = {
         ...config,
         severity: {
-          green: config.green || config.severity?.green || 0,
+          green: config.green || config.severity?.green,
           yellow: config.yellow || config.severity?.yellow || 0,
           red: config.red || config.severity?.red || 0,
         },
@@ -170,9 +171,7 @@ export class HuiGaugeCardEditor
     fireEvent(this, "config-changed", { config });
   }
 
-  private _computeLabelCallback = (
-    schema: SchemaUnion<ReturnType<typeof this._schema>>
-  ) => {
+  private _computeLabelCallback = (schema: SchemaUnion<typeof SCHEMA>) => {
     switch (schema.name) {
       case "name":
         return this.hass!.localize(