init: add source code from src.zip

src/hooks/useDynamicConfig.ts

@@ -0,0 +1,22 @@
+import React from 'react'
+import { getDynamicConfig_BLOCKS_ON_INIT } from '../services/analytics/growthbook.js'
+
+/**
+ * React hook for dynamic config values.
+ * Returns the default value initially, then updates when the config is fetched.
+ */
+export function useDynamicConfig<T>(configName: string, defaultValue: T): T {
+  const [configValue, setConfigValue] = React.useState<T>(defaultValue)
+
+  React.useEffect(() => {
+    if (process.env.NODE_ENV === 'test') {
+      // Prevents a test hang when using this hook in tests
+      return
+    }
+    void getDynamicConfig_BLOCKS_ON_INIT<T>(configName, defaultValue).then(
+      setConfigValue,
+    )
+  }, [configName, defaultValue])
+
+  return configValue
+}