Throw errors when problems happen so we get non-zero exit codes (#240)

* Throw errors when problems happen so we get non-zero exit codes

* Add test case for output failure

* Fix tslint issues

Author: palfrey

test/error.test.ts

@@ -0,0 +1,12 @@
+import { assert } from "chai";
+import { exec, getDefaultArgs } from "../typescript-json-schema";
+import * as path from "path";
+
+describe("error", () => {
+    it("error-check", () => {
+        assert.throws(() => {
+            // This needs a valid path. "dates" chosen basically at random
+            exec(path.resolve(__dirname, "./programs/dates/"), "MyObject", getDefaultArgs());
+        }, Error, "No output definition. Probably caused by errors prior to this?");
+    });
+});

typescript-json-schema.ts

@@ -1195,14 +1195,14 @@ export function exec(filePattern: string, fullTypeName: string, args = getDefaul
 
     const definition = generateSchema(program, fullTypeName, args, onlyIncludeFiles);
     if (definition === null) {
-        return;
+        throw new Error("No output definition. Probably caused by errors prior to this?");
     }
 
     const json = stringify(definition, {space: 4}) + "\n\n";
     if (args.out) {
         require("fs").writeFile(args.out, json, function(err: Error) {
             if (err) {
-                console.error("Unable to write output file: " + err.message);
+                throw new Error("Unable to write output file: " + err.message);
             }
         });
     } else {