ESLint: enforce import formatting

Mainly to reduce merge conflict noise

- Order by origin & alphabetically
- Imports should be at the top of the file
- Newline between imports & the rest of the file
- Disallow duplicate imports
- Enforce single-line when only importing one object
- Enforce multi-line when importing two or more

.eslintrc.json

@@ -9,7 +9,9 @@
     "unused-imports",
     "eslint-plugin-lodash",
     "eslint-plugin-jsonc",
-    "eslint-plugin-rxjs"
+    "eslint-plugin-rxjs",
+    "eslint-plugin-simple-import-sort",
+    "eslint-plugin-import-newlines"
   ],
   "overrides": [
     {
@@ -210,9 +212,23 @@
 
         "deprecation/deprecation": "warn",
 
+        "simple-import-sort/imports": "error",
+        "simple-import-sort/exports": "error",
         "import/order": "off",
+        "import/first": "error",
+        "import/newline-after-import": "error",
+        "import/no-duplicates": "error",
         "import/no-deprecated": "warn",
         "import/no-namespace": "error",
+        "import-newlines/enforce": [
+          "error",
+          {
+            "items": 1,
+            "semi": true,
+            "forceSingleLine": true
+          }
+        ],
+
         "unused-imports/no-unused-imports": "error",
         "lodash/import-scope": [
           "error",

package.json

@@ -169,10 +169,12 @@
     "eslint": "^8.39.0",
     "eslint-plugin-deprecation": "^1.4.1",
     "eslint-plugin-import": "^2.27.5",
+    "eslint-plugin-import-newlines": "^1.3.1",
     "eslint-plugin-jsdoc": "^39.6.4",
     "eslint-plugin-jsonc": "^2.6.0",
     "eslint-plugin-lodash": "^7.4.0",
     "eslint-plugin-rxjs": "^5.0.3",
+    "eslint-plugin-simple-import-sort": "^10.0.0",
     "eslint-plugin-unused-imports": "^2.0.0",
     "express-static-gzip": "^2.1.7",
     "jasmine-core": "^3.8.0",

yarn.lock

@@ -5296,6 +5296,11 @@ eslint-plugin-deprecation@^1.4.1:
     tslib "^2.3.1"
     tsutils "^3.21.0"
 
+eslint-plugin-import-newlines@^1.3.1:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-import-newlines/-/eslint-plugin-import-newlines-1.3.1.tgz#e21705667778e8134382b50079fbb2c8d3a2fcde"
+  integrity sha512-7vyhwliGm+CTwteRw2ym+IO9OaksGYmSt63elPPBM0QJ3zwRwMKtgHOSHVtdHlrSERRTVCsWtMO8dDdAdmHMXg==
+
 eslint-plugin-import@^2.27.5:
   version "2.27.5"
   resolved "https://registry.yarnpkg.com/eslint-plugin-import/-/eslint-plugin-import-2.27.5.tgz#876a6d03f52608a3e5bb439c2550588e51dd6c65"
@@ -5361,6 +5366,11 @@ eslint-plugin-rxjs@^5.0.3:
     tsutils "^3.0.0"
     tsutils-etc "^1.4.1"
 
+eslint-plugin-simple-import-sort@^10.0.0:
+  version "10.0.0"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-simple-import-sort/-/eslint-plugin-simple-import-sort-10.0.0.tgz#cc4ceaa81ba73252427062705b64321946f61351"
+  integrity sha512-AeTvO9UCMSNzIHRkg8S6c3RPy5YEwKWSQPx3DYghLedo2ZQxowPFLGDN1AZ2evfg6r6mjBSZSLxLFsWSu3acsw==
+
 eslint-plugin-unused-imports@^2.0.0:
   version "2.0.0"
   resolved "https://registry.npmjs.org/eslint-plugin-unused-imports/-/eslint-plugin-unused-imports-2.0.0.tgz"