feat: add support for ESM config files

.babelrc

@@ -10,5 +10,17 @@
   ],
   "ignore": [
     "src/assets"
-  ]
+  ],
+  "overrides": [{
+    "test": "./src/helpers/import-helper.js",
+    "presets": [
+      ["@babel/env", {
+        "targets": {
+          "node": "10.0"
+        },
+        "shippedProposals": true,
+        "exclude": ["proposal-dynamic-import"],
+      }]
+    ],
+  }]
 }

.gitignore

@@ -9,6 +9,7 @@ pids
 
 # Editor files
 .vscode
+.idea
 
 # Directory for instrumented libs generated by jscoverage/JSCover
 lib-cov

package.json

@@ -38,6 +38,7 @@
     "pg": "latest",
     "pg-hstore": "latest",
     "prettier": "^2.4.1",
+    "semver": "^7.3.5",
     "sequelize": "^6.9.0",
     "sqlite3": "latest",
     "through2": "^4.0.2"

src/helpers/config-helper.js

@@ -5,45 +5,41 @@ import _ from 'lodash';
 import { promisify } from 'util';
 import helpers from './index';
 import getYArgs from '../core/yargs';
+import importHelper from './import-helper';
 
 const args = getYArgs().argv;
 
 const api = {
   config: undefined,
   rawConfig: undefined,
   error: undefined,
-  init() {
-    return Promise.resolve()
-      .then(() => {
-        let config;
-
-        if (args.url) {
-          config = api.parseDbUrl(args.url);
-        } else {
-          try {
-            config = require(api.getConfigFile());
-          } catch (e) {
-            api.error = e;
-          }
-        }
-        return config;
-      })
-      .then((config) => {
-        if (typeof config === 'object' || config === undefined) {
-          return config;
-        } else if (config.length === 1) {
-          return promisify(config)();
-        } else {
-          return config();
-        }
-      })
-      .then((config) => {
-        api.rawConfig = config;
-      })
-      .then(() => {
-        // Always return the full config api
-        return api;
-      });
+  async init() {
+    let config;
+
+    try {
+      if (args.url) {
+        config = api.parseDbUrl(args.url);
+      } else {
+        const module = await importHelper.importModule(api.getConfigFile());
+        config = await module.default;
+      }
+    } catch (e) {
+      api.error = e;
+    }
+
+    if (typeof config === 'function') {
+      // accepts callback parameter
+      if (config.length === 1) {
+        config = await promisify(config)();
+      } else {
+        // returns a promise.
+        config = await config();
+      }
+    }
+
+    api.rawConfig = config;
+
+    return api;
   },
   getConfigFile() {
     if (args.config) {

src/helpers/dummy-file.js

@@ -0,0 +1 @@
+// this file is imported by import-helper to detect whether dynamic imports are supported.

src/helpers/import-helper.js

@@ -0,0 +1,35 @@
+async function supportsDynamicImport() {
+  try {
+    // imports are cached.
+    // no need to worry about perf here.
+    // Don't remove .js: extension must be included for ESM imports!
+    await import('./dummy-file.js');
+    return true;
+  } catch (e) {
+    return false;
+  }
+}
+
+/**
+ * Imports a JSON, CommonJS or ESM module
+ * based on feature detection.
+ *
+ * @param modulePath path to the module to import
+ * @returns {Promise<unknown>} the imported module.
+ */
+async function importModule(modulePath) {
+  // JSON modules are still behind a flag. Fallback to require for now.
+  // https://nodejs.org/api/esm.html#json-modules
+  if (!modulePath.endsWith('.json') && (await supportsDynamicImport())) {
+    return import(modulePath);
+  }
+
+  // mimics what `import()` would return for
+  // cjs modules.
+  return { default: require(modulePath) };
+}
+
+module.exports = {
+  supportsDynamicImport,
+  importModule,
+};

test/db/migrate.test.js

@@ -3,6 +3,7 @@ const expect = require('expect.js');
 const Support = require(__dirname + '/../support');
 const helpers = require(__dirname + '/../support/helpers');
 const gulp = require('gulp');
+const semver = require('semver');
 const _ = require('lodash');
 
 [
@@ -25,7 +26,7 @@ const _ = require('lodash');
     let configPath = 'config/';
     let migrationFile = options.migrationFile || 'createPerson';
     const config = _.assign({}, helpers.getTestConfig(), options.config);
-    let configContent = JSON.stringify(config);
+    let configContent = JSON.stringify(config, null, 2);
 
     if (!migrationFile.match(/\.(cjs|ts)$/)) {
       migrationFile = migrationFile + '.js';
@@ -70,7 +71,11 @@ const _ = require('lodash');
     it('creates a SequelizeMeta table', function (done) {
       const self = this;
 
-      prepare(() => {
+      prepare((e) => {
+        if (e) {
+          return done(e);
+        }
+
         helpers.readTables(self.sequelize, (tables) => {
           expect(tables).to.have.length(2);
           expect(tables).to.contain('SequelizeMeta');
@@ -293,6 +298,58 @@ describe(Support.getTestDialectTeaser('db:migrate'), () => {
   });
 });
 
+describeOnlyForESM(Support.getTestDialectTeaser('db:migrate'), () => {
+  describe('with config.mjs', () => {
+    const prepare = function (callback) {
+      const config = helpers.getTestConfig();
+      const configContent = 'export default ' + JSON.stringify(config);
+      let result = '';
+
+      return gulp
+        .src(Support.resolveSupportPath('tmp'))
+        .pipe(helpers.clearDirectory())
+        .pipe(helpers.runCli('init'))
+        .pipe(helpers.removeFile('config/config.json'))
+        .pipe(helpers.copyMigration('createPerson.js'))
+        .pipe(helpers.overwriteFile(configContent, 'config/config.mjs'))
+        .pipe(helpers.runCli('db:migrate --config config/config.mjs'))
+        .on('error', (e) => {
+          callback(e);
+        })
+        .on('data', (data) => {
+          result += data.toString();
+        })
+        .on('end', () => {
+          callback(null, result);
+        });
+    };
+
+    it('creates a SequelizeMeta table', function (done) {
+      prepare((e) => {
+        if (e) {
+          return done(e);
+        }
+
+        helpers.readTables(this.sequelize, (tables) => {
+          expect(tables).to.have.length(2);
+          expect(tables).to.contain('SequelizeMeta');
+          done();
+        });
+      });
+    });
+
+    it('creates the respective table', function (done) {
+      prepare(() => {
+        helpers.readTables(this.sequelize, (tables) => {
+          expect(tables).to.have.length(2);
+          expect(tables).to.contain('Person');
+          done();
+        });
+      });
+    });
+  });
+});
+
 describe(Support.getTestDialectTeaser('db:migrate'), () => {
   describe('with config.json and url option', () => {
     const prepare = function (callback) {
@@ -525,3 +582,11 @@ describe(Support.getTestDialectTeaser('db:migrate'), () => {
     });
   });
 });
+
+function describeOnlyForESM(title, fn) {
+  if (semver.satisfies(process.version, '^12.20.0 || ^14.13.1 || >=16.0.0')) {
+    describe(title, fn);
+  } else {
+    describe.skip(title, fn);
+  }
+}