fix: add support for typescript 2.6 (#74)

package.json

@@ -38,7 +38,7 @@
   "author": "Google Inc.",
   "license": "Apache-2.0",
   "dependencies": {
-    "chalk": "^2.2.0",
+    "chalk": "^2.3.0",
     "clang-format": "^1.0.53",
     "inquirer": "^3.2.1",
     "meow": "^3.7.0",
@@ -54,7 +54,7 @@
     "@types/make-dir": "^1.0.1",
     "@types/meow": "^3.6.2",
     "@types/ncp": "^2.0.0",
-    "@types/node": "^8.0.17",
+    "@types/node": "^8.0.47",
     "@types/pify": "3.0.0",
     "@types/rimraf": "2.0.2",
     "@types/tmp": "0.0.33",
@@ -66,7 +66,7 @@
     "nyc": "^11.2.1",
     "source-map-support": "^0.5.0",
     "tmp": "0.0.31",
-    "typescript": "~2.4.1"
+    "typescript": "~2.6.1"
   },
   "peerDependencies": {
     "typescript": "^2.4.1"

test/test-kitchen.ts

@@ -22,18 +22,33 @@ const simpleExecp = pify(cp.exec);
 const renamep = pify(fs.rename);
 const ncpp = pify(ncp.ncp);
 
+// TODO: improve the typedefinitions in @types/node. Right now they specify
+// the return type to be Error.
+interface ExecError extends Error {
+  code: number;
+}
+
+function isExecError(err: Error|ExecError): err is ExecError {
+  return (<ExecError>err).code !== undefined;
+}
+
 // cp.exec doesn't fit the (err ^ result) pattern because a process can write
 // to stdout/stderr and still exit with error code != 0.
 // In most cases simply promisifying cp.exec is adequate, but it's not if we
 // need to see console output for a process that exited with a non-zero exit
 // code, so we define a more exhaustive promsified cp.exec here.
+// TODO: replace this code with a npm modules that promisifies exec.
 const execp =
     (command: string, execOptions?: cp.ExecOptions): Promise<ExecResult> => {
       return new Promise((resolve) => {
         cp.exec(
             command, execOptions || {},
-            (err: Error&{code: number}, stdout, stderr) => {
-              resolve({exitCode: err ? err.code : 0, stdout, stderr});
+            (err: Error|ExecError|null, stdout, stderr) => {
+              resolve({
+                exitCode: err && isExecError(err) ? err.code : 0,
+                stdout,
+                stderr
+              });
             });
       });
     };