Make the default groups safely re-orderable

Closes #47.

Author: lydell

README.md

@@ -305,7 +305,7 @@ type Options = {
 
 Each string is a regex (with the `u` flag) and defines a group. (Remember to escape backslashes – it’s `"\\w"`, not `"\w"`, for example.)
 
-Each `import` is matched against _all_ regexes on the `from` string. The import ends up in the group with **the longest match.** In case of a tie, the first matching group wins.
+Each `import` is matched against _all_ regexes on the `from` string. The import ends up in the group with **the longest match.** In case of a tie, the **first** matching group wins.
 
 > If an import ends up in the wrong group – try making the desired group regex match more of the `from` string, or use negative lookahead (`(?!x)`) to exclude things from other groups.
 
@@ -327,8 +327,8 @@ These are the default groups:
   // Things that start with a letter (or digit or underscore), or `@` followed by a letter.
   ["^@?\\w"],
   // Absolute imports and other imports such as Vue-style `@/foo`.
-  // Anything that does not start with a dot.
-  ["^[^.]"],
+  // Anything not matched in another group.
+  ["^"],
   // Relative imports.
   // Anything that starts with a dot.
   ["^\\."],

examples/.eslintrc.js

@@ -98,7 +98,19 @@ module.exports = {
           "error",
           {
             // The default grouping, but with no blank lines.
-            groups: [["^\\u0000", "^@?\\w", "^[^.]", "^\\."]],
+            groups: [["^\\u0000", "^@?\\w", "^", "^\\."]],
+          },
+        ],
+      },
+    },
+    {
+      files: ["groups.default-reverse.js"],
+      rules: {
+        sort: [
+          "error",
+          {
+            // The default grouping, but in reverse.
+            groups: [["^\\."], ["^"], ["^@?\\w"], ["^\\u0000"]],
           },
         ],
       },

examples/groups.default-reverse.js

@@ -0,0 +1,6 @@
+import "./polyfills";
+import react from "react";
+import { storiesOf } from "@storybook/react";
+import App from "@/App";
+import styles from "./styles";
+import config from "/config";

src/sort.js

@@ -7,8 +7,8 @@ const defaultGroups = [
   // Things that start with a letter (or digit or underscore), or `@` followed by a letter.
   ["^@?\\w"],
   // Absolute imports and other imports such as Vue-style `@/foo`.
-  // Anything that does not start with a dot.
-  ["^[^.]"],
+  // Anything not matched in another group.
+  ["^"],
   // Relative imports.
   // Anything that starts with a dot.
   ["^\\."],

test/__snapshots__/examples.test.js.snap

@@ -101,6 +101,19 @@ import styles from "./styles.scss";
 
 `;
 
+exports[`examples groups.default-reverse.js 1`] = `
+import styles from "./styles";
+
+import App from "@/App";
+import config from "/config";
+
+import { storiesOf } from "@storybook/react";
+import react from "react";
+
+import "./polyfills";
+
+`;
+
 exports[`examples groups.no-blank-lines.js 1`] = `
 import classnames from "classnames";
 import PropTypes from "prop-types";

test/sort.test.js

@@ -923,6 +923,7 @@ const baseTests = (expect) => ({
           |import {} from "lodash/fp";
           |import {} from "react";
           |
+          |import {} from "";
           |import {} from "@/components/Alert"
           |import {} from "@/components/error.vue"
           |import {} from "/";
@@ -960,8 +961,6 @@ const baseTests = (expect) => ({
           |import img2 from "./img2";
           |import img10 from "./img10";
           |import {} from ".a";
-          |
-          |import {} from "";
         `);
       },
       errors: 1,