diff --git a/src/config-consumer/index.js b/src/config-consumer/index.ts
similarity index 94%
rename from src/config-consumer/index.js
rename to src/config-consumer/index.ts
index a98c73d98..b6a26526b 100644
--- a/src/config-consumer/index.js
+++ b/src/config-consumer/index.ts
@@ -1,2 +1,2 @@
 /* istanbul ignore file */
-export { default as NConfigConsumer } from './src/ConfigConsumer.js'
+export { default as NConfigConsumer } from './src/ConfigConsumer'
diff --git a/src/config-consumer/src/ConfigConsumer.js b/src/config-consumer/src/ConfigConsumer.ts
similarity index 87%
rename from src/config-consumer/src/ConfigConsumer.js
rename to src/config-consumer/src/ConfigConsumer.ts
index b6b3c96cc..7598f9fb5 100644
--- a/src/config-consumer/src/ConfigConsumer.js
+++ b/src/config-consumer/src/ConfigConsumer.ts
@@ -1,4 +1,5 @@
 import { defineComponent, inject, toRef, watch } from 'vue'
+import { ConfigProviderInjection } from '../../config-provider'
 import useLegacy from './use-legacy'
 
 export default defineComponent({
@@ -24,7 +25,10 @@ export default defineComponent({
     }
   },
   setup (props) {
-    const NConfigProvider = inject('NConfigProvider', null)
+    const NConfigProvider = inject<ConfigProviderInjection | null>(
+      'NConfigProvider',
+      null
+    )
     if (NConfigProvider) {
       watch(toRef(NConfigProvider, 'mergedNamespace'), (value, oldValue) => {
         const { onNamespaceChange } = props
diff --git a/src/config-consumer/src/use-legacy.js b/src/config-consumer/src/use-legacy.ts
similarity index 69%
rename from src/config-consumer/src/use-legacy.js
rename to src/config-consumer/src/use-legacy.ts
index d7abb2ad6..c9181ff8c 100644
--- a/src/config-consumer/src/use-legacy.js
+++ b/src/config-consumer/src/use-legacy.ts
@@ -1,7 +1,18 @@
 import { computed, watch, toRef } from 'vue'
+import { ConfigProviderInjection } from '../../config-provider'
 import styleScheme from '../../_deprecated/style-scheme'
 
-export default function useLegacy (NConfigProvider, props) {
+interface UseLegacyProps {
+  onLanguageChange: (
+    lang: string | undefined,
+    oldLang: string | undefined
+  ) => void
+}
+
+export default function useLegacy (
+  NConfigProvider: ConfigProviderInjection | null,
+  props: UseLegacyProps
+) {
   if (NConfigProvider) {
     watch(toRef(NConfigProvider, 'mergedLanguage'), (value, oldValue) => {
       const { onLanguageChange } = props
@@ -22,7 +33,7 @@ export default function useLegacy (NConfigProvider, props) {
         : null
     }),
     legacyStyleScheme: computed(() => {
-      return styleScheme[NConfigProvider.mergedTheme || 'light']
+      return (styleScheme as any)[NConfigProvider?.mergedTheme || 'light']
     })
   }
 }