refactor: organise TypeScript config and migrate helpers (#44747)

* feat: allow more 1000 steps to be created at once

* refactor: start migrating to typescript

* refactor: delete-step to ts

* refactor: migrated some helpers

* refactor: migrate create-empty-steps

* refactor: migrate create-step-between

* refactor: finish migrating to TS

* refactor: migrate tests

* fix: ensure mock.restore is done after each test

* fix: prevent double-tscing

* fix: repair the tests

* chore: use ts-node for scripts

We don't need the performance boost of incremental compilation and
ts-node is easier to work with

* refactor: consolidate tsconfigs

* refactor: replace gulp

* fix: use ts-node for build-curriculum

* fix: allow ts compilation of config

* feat: create and use create:config script

* fix: add /config to eslint projects

* fix: remove gulp script

tools/challenge-helper-scripts/utils.test.ts

@@ -0,0 +1,138 @@
+import fs from 'fs';
+import ObjectID from 'bson-objectid';
+import glob from 'glob';
+import mock from 'mock-fs';
+
+// NOTE:
+// Use `console.log()` before mocking the filesystem or use
+// `process.stdout.write()` instead. There are issues when using `mock-fs` and
+// `require`.
+
+jest.mock('bson-objectid', () => {
+  return jest.fn(() => ({ toString: () => mockChallengeId }));
+});
+
+jest.mock('./helpers/get-step-template', () => {
+  return {
+    getStepTemplate: jest.fn(() => 'Mock template...')
+  };
+});
+
+jest.mock('./helpers/get-project-meta-path', () => {
+  return {
+    getProjectMetaPath: jest.fn(() => '_meta/project/meta.json')
+  };
+});
+
+jest.mock('./helpers/get-project-path', () => {
+  return {
+    getProjectPath: jest.fn(() => 'project/')
+  };
+});
+
+jest.mock('gray-matter', () => {
+  return {
+    read: jest.fn(() => ({
+      data: { id: mockChallengeId }
+    })),
+    stringify: jest.fn(() => 'Lorem ipsum...')
+  };
+});
+
+jest.mock(
+  '../challenge-helper-scripts/helpers/get-project-path-metadata',
+  () => ({
+    getMetaData: jest.fn(() => ({
+      id: 'mock-id'
+    }))
+  })
+);
+
+const mockChallengeId = '60d35cf3fe32df2ce8e31b03';
+import { getStepTemplate } from './helpers/get-step-template';
+import { createStepFile, reorderSteps } from './utils';
+
+describe('Challenge utils helper scripts', () => {
+  describe('createStepFile util', () => {
+    it('should create next step and return its identifier', () => {
+      mock({
+        'project/': {
+          'step-001.md': 'Lorem ipsum...',
+          'step-002.md': 'Lorem ipsum...'
+        }
+      });
+
+      const step = createStepFile({
+        projectPath: 'project/',
+        stepNum: 3
+      });
+
+      expect(step.toString()).toEqual(mockChallengeId);
+      expect(ObjectID).toHaveBeenCalledTimes(1);
+
+      // Internal tasks
+      // - Should generate a template for the step that is being created
+      expect(getStepTemplate).toHaveBeenCalledTimes(1);
+
+      // - Should write a file with a given name and template
+      const files = glob.sync(`project/*.md`);
+
+      expect(files).toEqual([
+        `project/step-001.md`,
+        `project/step-002.md`,
+        `project/step-003.md`
+      ]);
+    });
+  });
+
+  describe('reorderSteps util', () => {
+    it('should sort files found in given path', () => {
+      mock({
+        '_meta/project/': {
+          'meta.json': 'Lorem ipsum meta content...'
+        },
+        'project/': {
+          'step-001.md': 'Lorem ipsum 1...',
+          'step-002.md': 'Lorem ipsum 2...',
+          'step-002b.md': 'Lorem ipsum 3...'
+        }
+      });
+
+      reorderSteps();
+
+      // - Should write a file with a given name and template
+      const files = glob.sync(`project/*.md`);
+
+      expect(files).toEqual([
+        'project/step-001.md',
+        'project/step-002.md',
+        'project/step-003.md'
+      ]);
+
+      const result = fs.readFileSync('_meta/project/meta.json', 'utf8');
+
+      const expectedResult = `{
+  "id": "mock-id",
+  "challengeOrder": [
+    [
+      "60d35cf3fe32df2ce8e31b03",
+      "Step 1"
+    ],
+    [
+      "60d35cf3fe32df2ce8e31b03",
+      "Step 2"
+    ],
+    [
+      "60d35cf3fe32df2ce8e31b03",
+      "Step 3"
+    ]
+  ]
+}`;
+
+      expect(result).toEqual(expectedResult);
+    });
+  });
+  afterEach(() => {
+    mock.restore();
+  });
+});