refactor: add template resolver pipeline#7490
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janechu merged 9 commits intomicrosoft:releases/fast-element-v3from Apr 24, 2026
Merged
refactor: add template resolver pipeline#7490janechu merged 9 commits intomicrosoft:releases/fast-element-v3from
janechu merged 9 commits intomicrosoft:releases/fast-element-v3from
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Move FASTElement definition orchestration to a function-based template resolver pipeline so extensions run before template resolution and concrete templates are assigned before registration. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Drop the templateOptions defer-and-hydrate API from fast-element so the core resolver pipeline no longer preserves the old deferred-template registration path. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
chrisdholt
approved these changes
Apr 24, 2026
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
janechu
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Apr 24, 2026
# Pull Request ## 📖 Description Adds a new **Declarative HTML** documentation section to the 3.x docs site with four pages covering the full declarative template authoring workflow: - **Overview** — Purpose of declarative templates, when to use them, a hello world example, and comparison with imperative `html` tagged templates. - **Writing f-templates** — Template syntax including content/attribute/boolean/event bindings, directives (`f-when`, `f-repeat`, `f-ref`, `f-slotted`, `f-children`), dot-notation paths, execution context access (`$e`, `$c`), and expression limitations. - **Defining Elements** — `TemplateElement` registration, `templateOptions: "defer-and-hydrate"`, lifecycle callbacks (`config()`), element configuration (`options()`), `observerMap` and `attributeMap` usage. - **Server-Side Rendering** — The renderer-agnostic SSR contract, hydration flow, Declarative Shadow DOM output, state propagation, and `@microsoft/fast-build` CLI usage. Also adds cross-references from `packages/fast-element/README.md` and `DECLARATIVE_HTML.md` to the new docs. Based on the declarative template features from PRs #7490, #7491, #7492, and #7493. ## 📑 Test Plan - Website builds successfully with `npm run build -w sites/website` - All four pages render correctly in the 11ty output - `npm run checkchange` passes (no change files needed for docs-only changes to the website) ## ✅ Checklist ### General - [x] I have included a change request file using `$ npm run change` - [ ] I have added tests for my changes. - [x] I have tested my changes. - [x] I have updated the project documentation to reflect my changes. - [x] I have read the [CONTRIBUTING](https://github.com/microsoft/fast/blob/main/CONTRIBUTING.md) documentation and followed the [standards](https://github.com/microsoft/fast/blob/main/CODE_OF_CONDUCT.md#our-standards) for this project.
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Pull Request
📖 Description
This draft lays the groundwork for definition-aware template resolution in
@microsoft/fast-element.PartialFASTElementDefinition.templateas either a concrete template or a function-based resolverFASTElementDefinition.templateconcrete by resolving async templates before registration completes👩💻 Reviewer Notes
This is the stack base for the declarative-template work. The main areas to review are the resolver API shape in
fast-definitions.tsand the updatedFASTElement.define()sequencing.📑 Test Plan
npm run build:tsc -w @microsoft/fast-elementnpm run doc -w @microsoft/fast-elementnpx @biomejs/biome check --colors=off packages/fast-element/src/components/fast-definitions.pw.spec.ts packages/fast-element/src/components/fast-definitions.ts packages/fast-element/src/components/fast-element.pw.spec.ts packages/fast-element/src/components/fast-element.ts packages/fast-element/src/index.tsnpm run checkchangenpx playwright test src/components/fast-definitions.pw.spec.ts src/components/fast-element.pw.spec.ts --project=chromium✅ Checklist
General
$ npm run change⏭ Next Steps
Follow-up draft PRs will build the declarative
<f-template>publication path, adddeclarativeTemplate(), and then remove the remainingsideEffectsmetadata.