add filter

Author: satackey

src/LayerCache.ts

@@ -60,15 +60,15 @@ class LayerCache {
   }
 
   private async separateAllLayerCaches() {
-    await this.moveLayerTars(this.getUnpackedTarDir(), this.getLayerCachesDir())
+    await this.moveLayerTarsInDir(this.getUnpackedTarDir(), this.getLayerCachesDir())
   }
 
   private async joinAllLayerCaches() {
-    await this.moveLayerTars(this.getLayerCachesDir(), this.getUnpackedTarDir())
+    await this.moveLayerTarsInDir(this.getLayerCachesDir(), this.getUnpackedTarDir())
   }
 
-  private async moveLayerTars(fromDir: string, toDir: string) {
-    const layerTars = (await exec.exec(`find . -name layer.tar`, [], { cwd: fromDir })).stdoutStr.split(`\n`)
+  private async moveLayerTarsInDir(fromDir: string, toDir: string) {
+    const layerTars = (await exec.exec(`find . -name layer.tar`, [], { cwd: fromDir })).stdoutStr.split(`\n`).filter(tar => tar !== '')
     const moveLayer = async (layer: string) => {
       const from = path.resolve(`${fromDir}/${layer}`)
       const to = path.resolve(`${toDir}/${layer}`)