feat(builder): accept and forward the dev-server hmr option (#145)

Cargo.toml

@@ -3,7 +3,7 @@ resolver = "2"
 members = ["crates/cli", "crates/diagnostics", "crates/project-resolver", "crates/ts-transform", "crates/bundler", "crates/template-compiler", "crates/npm-resolver", "crates/linker", "crates/watch", "crates/dev-server"]
 
 [workspace.package]
-version = "0.10.17"
+version = "0.10.18"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 authors = ["lukekania"]

packages/builder/schemas/dev-server.json

@@ -73,6 +73,10 @@
       "type": "object",
       "additionalProperties": { "type": "string" },
       "description": "Custom HTTP response headers emitted on every served response (static assets, the SPA-fallback index.html, and the SSE live-reload stream). Use this to serve production-like security headers (CSP, Cross-Origin-Opener-Policy), CORS headers, or cache-control overrides in dev. Headers the dev server sets itself (Content-Type, Cache-Control) are not overridden. Headers are not added to proxy-forwarded responses, which keep their upstream headers."
+    },
+    "hmr": {
+      "type": "boolean",
+      "description": "Enable Hot Module Replacement: edits to component templates and styles (and global stylesheets) are applied in place without a full page reload, preserving component and form state. TypeScript edits still trigger a full reload. When unset, the spawned binary falls back to `architect.serve.options.hmr` in angular.json (default false, matching today's full-reload behavior)."
     }
   },
   "additionalProperties": false

packages/builder/src/serve/__tests__/options.test.ts

@@ -226,6 +226,24 @@ describe('translateOptions', () => {
     ).not.toContain('--headers');
     expect(translateOptions(base, '/ws').args).not.toContain('--headers');
   });
+
+  it('forwards hmr: true as --hmr', () => {
+    const t = translateOptions({ ...base, hmr: true }, '/ws');
+    expect(t.args).toContain('--hmr');
+    expect(t.args).not.toContain('--no-hmr');
+  });
+
+  it('forwards hmr: false as --no-hmr', () => {
+    const t = translateOptions({ ...base, hmr: false }, '/ws');
+    expect(t.args).toContain('--no-hmr');
+    expect(t.args).not.toContain('--hmr');
+  });
+
+  it('omits both hmr flags when hmr is unset so the binary inherits angular.json', () => {
+    const args = translateOptions(base, '/ws').args;
+    expect(args).not.toContain('--hmr');
+    expect(args).not.toContain('--no-hmr');
+  });
 });
 
 describe('formatUrl', () => {

packages/builder/src/serve/options.ts

@@ -17,6 +17,7 @@ export interface DevServerOptions extends json.JsonObject {
   servePath: string | null;
   allowedHosts: string[] | null;
   headers: { [key: string]: string } | null;
+  hmr: boolean | null;
 }
 
 export interface TranslatedServeArgs {
@@ -95,6 +96,14 @@ export function translateOptions(
   if (headers !== null) {
     args.push('--headers', headers);
   }
+  // `hmr` is tri-state: an explicit true/false becomes `--hmr`/`--no-hmr`
+  // (the CLI override flags), while unset forwards nothing so the binary
+  // falls back to `architect.serve.options.hmr` in angular.json.
+  if (raw.hmr === true) {
+    args.push('--hmr');
+  } else if (raw.hmr === false) {
+    args.push('--no-hmr');
+  }
   args.push(...sslArgs);
 
   return {