Add context util

packages/lib/Context.ts

@@ -0,0 +1,13 @@
+const ctx = new Map<string, any>()
+
+export const getContext = (k: string) => ctx.get(k)
+
+export const setContext = (k: string, d: any) => ctx.set(k, d)
+
+export const withContext = (k: string, d: any, f: () => void) => {
+  const o = ctx.get(k)
+
+  ctx.set(k, d)
+  f()
+  ctx.set(k, o)
+}

packages/lib/index.ts

@@ -1,3 +1,4 @@
+export * from './Context'
 export * from './Deferred'
 export * from './Emitter'
 export * from './Fluent'