feat: define exit code in js level

Author: jcs090218

src/env.js

@@ -33,5 +33,14 @@ process.env.EMACS = EASK_EMACS;  // Set back the value.
 global.TITLE_CMD_OPTION = 'Command Options:';
 global.TITLE_PROXY_OPTION = 'Proxy Options:';
 
+/* Exit Code
+ *
+ * This must match with the variable `eask--exit-code` in
+ * the file `lisp/_prepare.el`.
+ */
+global.EXIT_SUCCESS = 0;
+global.EXIT_FAILURE = 1;
+global.EXIT_MISUSE  = 2;
+
 /* CI */
 global.GITHUB_ACTIONS = (process.env.GITHUB_WORKSPACE !== undefined);

src/util.js

@@ -230,7 +230,7 @@ async function e_call(argv, script, ...args) {
   }
 
   if (!_check_argv(argv)) {
-    process.exit(1);
+    process.exit(EXIT_FAILURE);
     return;
   }
 

test/jest/README.md

@@ -0,0 +1,3 @@
+# Jest Testing
+
+See the full documentation in https://emacs-eask.github.io/Contributing/Developing-Eask/#-testing.

test/jest/helpers.js

@@ -3,6 +3,9 @@ const exec = util.promisify(require("node:child_process").exec);
 const fs = require("node:fs/promises");
 const path = require("node:path");
 
+// Load the environment.
+const env = require('../../src/env');
+
 /*
  * This file uses JsDoc syntax.
  * Documentation for type helpers like @param: https://jsdoc.app/tags-type

test/jest/options.test.js

@@ -25,7 +25,7 @@ describe("options", () => {
 
     it("should error if the number is omitted before the next option", async () => {
       await expect(ctx.runEask("info -v --no-color")).rejects.toMatchObject({
-        code: 1,
+        code: EXIT_FAILURE,
       });
     });
   });