try to create config dir (default: ~/.mediachain/aleph) if it doesn't…

… exist

package.json

@@ -40,6 +40,7 @@
     "libp2p-websockets": "0.9.1",
     "lodash": "^4.17.1",
     "mafmt": "^2.1.2",
+    "mkdirp": "https://registry.npmjs.org/mkdirp/-/mkdirp-0.5.1.tgz",
     "multiaddr": "2.1.0",
     "multihashes": "^0.2.2",
     "multihashing": "^0.2.1",

src/peer/repl/index.js

@@ -1,8 +1,21 @@
 // @flow
 
 const os = require('os')
+const path = require('path')
+const mkdirp = require('mkdirp')
 // TODO: for bonus points, specify this as option, too
-const home = os.homedir() + '/.mediachain/aleph/'
+const home = path.join(os.homedir(), '.mediachain', 'aleph')
+
+function ensureDirExists (filePath: string, fileDescription = 'file') {
+  const basedir = path.dirname(filePath)
+  try {
+    mkdirp.sync(basedir)
+  } catch (err) {
+    throw new Error(
+      `Unable to create parent directory for ${fileDescription} at ${filePath}: ${err.message}`)
+  }
+  return filePath
+}
 
 require('yargs')
   .usage('Usage: $0 [options] <command> [command-options]')
@@ -15,16 +28,18 @@ require('yargs')
       // this is the only way to get useful config in subcommands
       'config': true,
       'global': true,
-      'default': home + 'config.json'
+      'default': path.join(home, 'config.json')
     },
     'identityPath': {
       'global': true,
-      'default': home + 'identity.node'
+      'default': path.join(home, 'identity.node')
     },
     'remotePeer': {
       'global': true,
       'type': 'string',
       'describe': 'The remote peer to pair with (multiaddress)'
     }
   })
+  .coerce('config', filePath => ensureDirExists(filePath, 'config file'))
+  .coerce('identityPath', filePath => ensureDirExists(filePath, 'identity file'))
   .argv