general-add-value-summary

---

name: general-add-value-summary description: Add a value summary extension so a feature's typed value can be displayed compactly in collection views (e.g., table columns). Use when a feature or property editor already has a value type and needs a renderer for collection table cells. Two variants — simple (element only, no API call) and resolver (batch API resolution needed). Prerequisite: a value type constant must already exist — use the general-add-value-type skill first if it doesn't. allowed-tools: Read, Write, Edit, Grep, Glob

Add Value Summary

Add a valueSummary extension so a feature's values are rendered in collection views.

Foundational documentation

Read before proceeding:

• Value Summary — extension type, base classes, resolver contract, rules

Prerequisite

A value type constant (UMB_{FEATURE}_VALUE_TYPE) must already exist and be exported from the package index.ts. If it doesn't exist yet, use the general-add-value-type skill first.

What you need from the user

1. Feature name — kebab-case (e.g., color-picker, user-group)
2. Package path — where the feature lives (e.g., src/packages/property-editors/color-picker/)
3. Value type constant — the existing constant to bind to (e.g., UMB_COLOR_PICKER_VALUE_TYPE)
4. Resolver needed? — Yes if rendering requires an API call (resolving IDs to names). No if the raw value can be formatted directly.

If resolver is needed, also ask: 5. Resolved type — the TypeScript type after resolution (e.g., UmbUserGroupItemModel) 6. Repository to use — which item/detail repository resolves the values

---

Option A: Simple summary (no resolver)

Use when the raw value can be formatted or rendered without an API call — dates, booleans, strings, color hex codes, numeric ranges, etc.

Files to create

{package-path}/value-summary/
├── manifests.ts
└── {feature}-value-summary.element.ts

Step 1: Create the summary element

File: {package-path}/value-summary/{feature}-value-summary.element.ts

import { customElement, html } from '@umbraco-cms/backoffice/external/lit';
import { UmbValueSummaryElementBase } from '@umbraco-cms/backoffice/value-summary';

@customElement('umb-{feature}-value-summary')
export class Umb{Feature}ValueSummaryElement extends UmbValueSummaryElementBase<{TValue}> {
	override render() {
		if (!this._value) return html``;
		return html`<span>${this._value}</span>`;
	}
}

export { Umb{Feature}ValueSummaryElement as element };

declare global {
	interface HTMLElementTagNameMap {
		'umb-{feature}-value-summary': Umb{Feature}ValueSummaryElement;
	}
}

Adjust render() for the value type:

• Dates → this.localize.dateTime(value)
• Booleans → <umb-icon>
• References → tags or comma-separated names

Step 2: Create the manifest

File: {package-path}/value-summary/manifests.ts

import type { UmbExtensionManifest } from '@umbraco-cms/backoffice/extension-api';
import { UMB_{FEATURE}_VALUE_TYPE } from '../value-type/constants.js';

export const manifests: Array<UmbExtensionManifest> = [
	{
		type: 'valueSummary',
		kind: 'default',
		alias: 'Umb.ValueSummary.{Feature}',
		name: '{Feature} Value Summary',
		forValueType: UMB_{FEATURE}_VALUE_TYPE,
		element: () => import('./{feature}-value-summary.element.js'),
	},
];

Step 3: Wire manifests into parent

import { manifests as valueSummaryManifests } from './value-summary/manifests.js';

export const manifests: Array<UmbExtensionManifest> = [
	...valueSummaryManifests,
	// ... other manifests
];

Simple summary checklist

• Element extends UmbValueSummaryElementBase and exports as element
• Manifest uses kind: 'default', correct forValueType, lazy element import
• Manifests wired into parent manifests.ts
• Compiles: npm run compile

---

Option B: Summary with resolver (batch API resolution)

Use when displaying the value requires fetching data — e.g., resolving reference uniques to display names. The resolver receives all values from the entire column in one batch call.

Files to create

{package-path}/value-summary/
├── manifests.ts
├── {feature}-value-summary.element.ts
└── {feature}-value-summary.resolver.ts

Step 1: Create the summary element

Same pattern as Option A, Step 1. Pass {TResolved} as the generic instead of {TValue} — the element receives the resolved value in this._value, already correctly typed.

Step 2: Create the resolver

File: {package-path}/value-summary/{feature}-value-summary.resolver.ts

import type { UmbValueSummaryResolver } from '@umbraco-cms/backoffice/value-summary';
import { UmbControllerBase } from '@umbraco-cms/backoffice/class-api';
import { Umb{Entity}ItemRepository } from '../repository/item/{entity}-item.repository.js';

export class Umb{Feature}ValueSummaryResolver
	extends UmbControllerBase
	implements UmbValueSummaryResolver<{TValue}, {TResolved}>
{
	#repo = new Umb{Entity}ItemRepository(this);

	async resolveValues(values: ReadonlyArray<{TValue}>) {
		// Deduplicate all IDs needed across the entire batch
		const allUniques = [...new Set(values.flatMap((v) => /* extract IDs from v */))];

		const { data: items, asObservable } = await this.#repo.requestItems(allUniques);
		 (!items)  { : values.(     {}) };

		
		 {
			: values.( ),
			: asObservable
				?  ().(( values.( )))
				: ,
		};
	}
}

 { {}  valueResolver };

Critical rules:

• data must have the same length as values and be positionally aligned.
• Export the class as valueResolver (named export) — the loader checks for this name.
• Provide asObservable only when the resolved data can change after initial load.

Step 3: Create the manifest

File: {package-path}/value-summary/manifests.ts

import type { UmbExtensionManifest } from '@umbraco-cms/backoffice/extension-api';
import { UMB_{FEATURE}_VALUE_TYPE } from '../value-type/constants.js';

export const manifests: Array<UmbExtensionManifest> = [
	{
		type: 'valueSummary',
		kind: 'default',
		alias: 'Umb.ValueSummary.{Feature}',
		name: '{Feature} Value Summary',
		forValueType: UMB_{FEATURE}_VALUE_TYPE,
		element: () => import('./{feature}-value-summary.element.js'),
		valueResolver: () => import('./{feature}-value-summary.resolver.js'),
	},
];

Step 4: Wire manifests into parent

Same as Option A, Step 3.

Resolver checklist

• Element extends UmbValueSummaryElementBase, renders resolved type, exports as element
• Resolver extends UmbControllerBase, implements UmbValueSummaryResolver<{TValue}, {TResolved}>
• resolveValues() returns data positionally aligned with values (same length, same order)
• Resolver exported as valueResolver (named export)
• Manifest includes valueResolver: () => import(...) lazy loader
• asObservable included only if resolved data can change reactively
• Manifests wired into parent manifests.ts
• Compiles: npm run compile

---

Collection wiring

Property editors: no extra step needed. The document collection reads editorAlias from the server and matches it to your forValueType.

Generic table collection kind: set valueType in the collection manifest column:

{ field: 'myField', label: 'My Field', valueType: UMB_{FEATURE}_VALUE_TYPE }