feat(util): renderState

core/util/src/_logger.ts

@@ -0,0 +1,3 @@
+import {createLogger} from '@alwatr/logger';
+
+export const logger = createLogger('alwatr/util');

core/util/src/index.ts

@@ -5,3 +5,4 @@ export * from './client-id.js';
 export * from './polyfill.js';
 export * from './flat-str.js';
 export * from './string.js';
+export * from './render-state.js';

core/util/src/render-state.ts

@@ -0,0 +1,46 @@
+import {logger} from './_logger.js';
+
+export const renderState = <R, T extends string>(
+  state: T,
+  renderRecord: Record<T | '_default', undefined | T | (() => R)>,
+  thisArg: unknown = null,
+): R | void => {
+  logger.logMethodArgs?.('renderState', {state, renderRecord});
+
+  let render = renderRecord[state];
+
+  if (typeof render === 'string') {
+    render = renderRecord[render as T];
+  }
+
+  if (render === undefined) {
+    if (renderRecord._default === undefined) {
+      logger.error('renderState', 'invalid_render_state');
+      return;
+    }
+    // else
+    if (typeof renderRecord._default === 'string') {
+      if (renderRecord[renderRecord._default] === undefined) {
+        logger.error('renderState', 'invalid_default_render');
+        return;
+      }
+      // else
+      return renderState(renderRecord._default, renderRecord, thisArg);
+    }
+    // else
+    render = renderRecord._default;
+  }
+
+  if (typeof render !== 'function') {
+    logger.error('renderState', 'invalid_render_state');
+    return;
+  }
+
+  try {
+    return render.call(thisArg);
+  }
+  catch (err) {
+    logger.error('renderState', 'render_error', err);
+    return;
+  }
+};