test: add jest snapshot test

Author: Fonger

.eslintignore

@@ -1,2 +1,3 @@
-node_modules
-dist
+node_modules/
+dist/
+coverage/

.eslintrc

@@ -8,6 +8,9 @@
     "eslint:recommended",
     "plugin:@typescript-eslint/recommended"
   ],
+  "env": {
+    "node": true
+  },
   "rules": {
     "@typescript-eslint/no-unused-vars": ["error", { "args": "none" }]
   }

.github/workflows/test.yml

@@ -24,4 +24,5 @@ jobs:
         cache: 'yarn'
     - run: yarn install --frozen-lockfile
     - run: yarn lint
+    - run: yarn test
     - run: yarn build

.gitignore

@@ -1,5 +1,6 @@
 node_modules/
 dist/
+coverage/
 
 *.log
 *.swp

dprint.json

@@ -13,7 +13,8 @@
   "excludes": [
     "**/node_modules",
     "**/*-lock.json",
-    "dist"
+    "dist",
+    "coverage"
   ],
   "plugins": [
     "https://plugins.dprint.dev/typescript-0.62.2.wasm",

jest.config.js

@@ -0,0 +1,11 @@
+/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  globals: {
+    'ts-jest': {
+      isolatedModules: true,
+    },
+  },
+  testPathIgnorePatterns: ['dist'],
+};

package.json

@@ -21,14 +21,19 @@
     "build": "rm -rf dist && npm run build:cjs && npm run build:ejs",
     "build:cjs": "tsc --outDir dist/cjs --declaration",
     "build:ejs": "tsc --outDir dist/ejs --module es6",
+    "test": "jest --coverage",
     "lint": "dprint check && eslint .",
     "format": "dprint fmt"
   },
+  "files": ["dist"],
   "devDependencies": {
+    "@types/jest": "^27.4.0",
     "@typescript-eslint/eslint-plugin": "^5.10.2",
     "@typescript-eslint/parser": "^5.10.2",
     "dprint": "^0.22.0",
     "eslint": "^8.8.0",
+    "jest": "^27.4.7",
+    "ts-jest": "^27.1.3",
     "ttypescript": "^1.5.13",
     "typescript": "^4.5.5"
   },

src/__snapshots__/transform.test.ts.snap

@@ -0,0 +1,58 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`transform export const enum into object literal test-case/const-enum.d.ts 1`] = `
+"export declare enum SomeEnum {
+    A = 0,
+    B = 1,
+    C = \\"hello\\",
+    D = 1000,
+    E = 1001
+}
+export declare enum ComputedEnum {
+    A = 0,
+    B = 1,
+    C = 2,
+    D = -2,
+    E = 4,
+    F = -1,
+    G = 1228,
+    H = 31,
+    I = 230,
+    J = \\"12\\",
+    K = 1
+}
+export declare enum RegularEnum {
+    A = 0,
+    B = 1
+}
+"
+`;
+
+exports[`transform export const enum into object literal test-case/const-enum.js 1`] = `
+"export const SomeEnum = {
+    A: 0,
+    B: 1,
+    C: \\"hello\\",
+    D: 1000,
+    E: 1001
+};
+export const ComputedEnum = {
+    A: 0,
+    B: 1,
+    C: 2,
+    D: -2,
+    E: 4,
+    F: -1,
+    G: 1228,
+    H: 31,
+    I: 230,
+    J: \\"12\\",
+    K: 1
+};
+export var RegularEnum;
+(function (RegularEnum) {
+    RegularEnum[RegularEnum[\\"A\\"] = 0] = \\"A\\";
+    RegularEnum[RegularEnum[\\"B\\"] = 1] = \\"B\\";
+})(RegularEnum || (RegularEnum = {}));
+"
+`;

src/transform.test.ts

@@ -0,0 +1,44 @@
+import ts from 'typescript';
+import transform from './transform';
+
+describe('transform export const enum into object literal', () => {
+  const output = compile('test-case/const-enum.ts');
+
+  for (const [fileName, content] of Object.entries(output)) {
+    it(fileName, () => {
+      expect(content).toMatchSnapshot();
+    });
+  }
+});
+
+type Output = { [fileName: string]: string };
+function compile(fileName: string): Output {
+  const program = ts.createProgram({
+    rootNames: [fileName],
+    options: {
+      target: ts.ScriptTarget.ES2015,
+      module: ts.ModuleKind.ES2015,
+      preserveConstEnums: true,
+      declaration: true,
+      moduleResolution: ts.ModuleResolutionKind.NodeJs,
+    },
+  });
+
+  const transformer = transform(program);
+  const output: Output = {};
+
+  program.emit(
+    undefined,
+    (fileName, data) => {
+      output[fileName] = (output[fileName] || '') + data;
+    },
+    undefined,
+    false,
+    {
+      before: [transformer],
+      afterDeclarations: [transformer as any],
+    },
+  );
+
+  return output;
+}

src/transform.ts

@@ -1,7 +1,7 @@
 import ts from 'typescript';
 import { evaluate, hasModifier } from './utils';
 
-export default function(program: ts.Program, pluginOptions: unknown) {
+export default function(program: ts.Program, pluginOptions?: unknown) {
   return (ctx: ts.TransformationContext) => {
     return (sourceFile: ts.SourceFile) => {
       const ambient = sourceFile.isDeclarationFile;