add replace()

ts/smartgulp.gulpapi.ts

@@ -21,6 +21,15 @@ export let src = (minimatchPathArrayArg: string[]): Transform => {
   return gulpStream.stream
 }
 
-export let dest = () => {
+export let dest = (dirArg: string) => {
 
 }
+
+export let replace = () => {
+  return plugins.through2.obj(async (file: Smartfile, enc, cb) => {
+    await file.write()
+    cb(file)
+  }, (cb) => {
+    cb()
+  })
+}

ts/smartgulp.plugins.ts

@@ -2,10 +2,12 @@ import * as smartevent from 'smartevent'
 import * as smartfile from 'smartfile'
 import * as smartstream from 'smartstream'
 import * as lodash from 'lodash'
+import * as through2 from 'through2'
 
 export {
   lodash,
   smartevent,
   smartfile,
-  smartstream
+  smartstream,
+  through2
 }