feat(core): improve error messaging

src/interactive.ts

@@ -4,6 +4,7 @@ import { resolve } from 'path';
 import { WriteStream } from 'tty';
 import { Branch, Leaf, Node } from '.';
 import { renderToCli } from './lib/markdown';
+import { tryPanic } from './lib/try-panic';
 import { createTreeInterpreter, TreeInterpreter } from './machine/tree';
 import { isBranch, isLeaf } from './machine/tree/nodes';
 
@@ -29,8 +30,10 @@ const getChoices = (node: Branch): Answer[] =>
 
 export const run = async ({ sourcePath }: { sourcePath: string }) => {
   const dataPath = resolve(process.cwd(), sourcePath);
-  const source = require(dataPath);
-  const tree = await source.getHelpDocument();
+  const REQUIRE_ERROR = `Failed to require('${dataPath}');`;
+  const source = tryPanic(() => require(dataPath), REQUIRE_ERROR);
+  const GET_DOCUMENT_ERROR = `Failed to call getHelpDocument() from ${dataPath}`;
+  const tree = await tryPanic(() => source.getHelpDocument(), GET_DOCUMENT_ERROR);
   const interpreter = createTreeInterpreter(tree);
   start(interpreter);
 };

src/lib/try-panic.ts

@@ -0,0 +1,10 @@
+import chalk from 'chalk';
+
+export const tryPanic = (fn: (...args: any[]) => any, message: string) => {
+  try {
+    return fn();
+  } catch (err) {
+    console.error(chalk.red(message));
+    process.exit(1);
+  }
+};

src/markdown.ts

@@ -1,10 +1,13 @@
 import { resolve } from 'path';
 import { toMarkdownFile } from './lib/markdown';
+import { tryPanic } from './lib/try-panic';
 
 export const run = async ({ sourcePath }: { sourcePath: string }) => {
   const dataPath = resolve(process.cwd(), sourcePath);
-  const source = require(dataPath);
-  const tree = await source.getHelpDocument();
+  const REQUIRE_ERROR = `Failed to require('${dataPath}');`;
+  const source = tryPanic(() => require(dataPath), REQUIRE_ERROR);
+  const GET_DOCUMENT_ERROR = `Failed to call getHelpDocument() from ${dataPath}`;
+  const tree = await tryPanic(() => source.getHelpDocument(), GET_DOCUMENT_ERROR);
   const markdown = await toMarkdownFile(tree);
   console.log(markdown);
 };