Context API

src/react.js

@@ -1,7 +1,30 @@
-import {watch, reactive, toRefs, shallowRef, onUpdated, onMounted, onBeforeUnmount, isRef, isReactive} from 'vue';
+import {watch, reactive, toRefs, shallowRef, onUpdated, onMounted, onBeforeUnmount, isRef, isReactive, defineComponent, toRef, provide, inject, unref} from 'vue';
+
+function _createProviderComponent (token) {
+  return defineComponent({
+    props: ['value'],
+    setup (props, { slots }) {
+      provide(token, toRef(props, 'value'));
+      return () => slots.default();
+    },
+  });
+}
 
-export function createContext() {
-  return {}
+function _createConsumerComponent (token, defaultValue) {
+  return (props, { slots }) => {
+    const injection = unref(inject(token, defaultValue));
+    return slots.default(injection);
+  };
+}
+
+export function createContext(defaultValue) {
+  const token = Symbol();
+  return {
+    _defaultValue: defaultValue,
+    _token: token,
+    Provider: _createProviderComponent(token),
+    Consumer: _createConsumerComponent(token, defaultValue)
+  };
 }
 
 export function forwardRef() {
@@ -187,8 +210,7 @@ export function useRef(initialValue) {
 }
 
 export function useContext(context) {
-  // TODO
-  context;
+  return unref(inject(context._token, context._defaultValue));
 }
 
 export function useCallback(cb, deps) {