Update: add allowSeparatedGroups option to sort-imports (fixes #12951)

docs/rules/sort-imports.md

@@ -41,6 +41,7 @@ This rule accepts an object with its properties as
     * `all` = import all members provided by exported bindings.
     * `multiple` = import multiple members.
     * `single` = import single member.
+* `allowSeparatedGroups` (default: `false`)
 
 Default option settings are:
 
@@ -50,7 +51,8 @@ Default option settings are:
         "ignoreCase": false,
         "ignoreDeclarationSort": false,
         "ignoreMemberSort": false,
-        "memberSyntaxSortOrder": ["none", "all", "multiple", "single"]
+        "memberSyntaxSortOrder": ["none", "all", "multiple", "single"],
+        "allowSeparatedGroups": false
     }]
 }
 ```
@@ -226,6 +228,53 @@ import {a, b} from 'foo.js';
 
 Default is `["none", "all", "multiple", "single"]`.
 
+### `allowSeparatedGroups`
+
+When `true` the rule checks the sorting of import declaration statements only for those that appear on consecutive lines.
+
+In other words, a blank line or a comment line or line with any other statement after an import declaration statement will reset the sorting of import declaration statements.
+
+Examples of **incorrect** code for this rule with the `{ "allowSeparatedGroups": true }` option:
+
+```js
+/*eslint sort-imports: ["error", { "allowSeparatedGroups": true }]*/
+
+import b from 'foo.js';
+import c from 'bar.js';
+import a from 'baz.js';
+```
+
+Examples of **correct** code for this rule with the `{ "allowSeparatedGroups": true }` option:
+
+```js
+/*eslint sort-imports: ["error", { "allowSeparatedGroups": true }]*/
+
+import b from 'foo.js';
+import c from 'bar.js';
+
+import a from 'baz.js';
+```
+
+```js
+/*eslint sort-imports: ["error", { "allowSeparatedGroups": true }]*/
+
+import b from 'foo.js';
+import c from 'bar.js';
+// comment
+import a from 'baz.js';
+```
+
+```js
+/*eslint sort-imports: ["error", { "allowSeparatedGroups": true }]*/
+
+import b from 'foo.js';
+import c from 'bar.js';
+quux();
+import a from 'baz.js';
+```
+
+Default is `false`.
+
 ## When Not To Use It
 
 This rule is a formatting preference and not following it won't negatively affect the quality of your code. If alphabetizing imports isn't a part of your coding standards, then you can leave this rule disabled.

lib/rules/sort-imports.js

@@ -44,6 +44,10 @@ module.exports = {
                     ignoreMemberSort: {
                         type: "boolean",
                         default: false
+                    },
+                    allowSeparatedGroups: {
+                        type: "boolean",
+                        default: false
                     }
                 },
                 additionalProperties: false
@@ -66,6 +70,7 @@ module.exports = {
             ignoreDeclarationSort = configuration.ignoreDeclarationSort || false,
             ignoreMemberSort = configuration.ignoreMemberSort || false,
             memberSyntaxSortOrder = configuration.memberSyntaxSortOrder || ["none", "all", "multiple", "single"],
+            allowSeparatedGroups = configuration.allowSeparatedGroups || false,
             sourceCode = context.getSourceCode();
         let previousDeclaration = null;
 
@@ -115,9 +120,32 @@ module.exports = {
 
         }
 
+        /**
+         * Calculates number of lines between two nodes. It is assumed that the given `left` node appears before
+         * the given `right` node in the source code. Lines are counted from the end of the `left` node till the
+         * start of the `right` node. If the given nodes are on the same line, it returns `0`, same as if they were
+         * on two consecutive lines.
+         * @param {ASTNode} left node that appears before the given `right` node.
+         * @param {ASTNode} right node that appears after the given `left` node.
+         * @returns {number} number of lines between nodes.
+         */
+        function getNumberOfLinesBetween(left, right) {
+            return Math.max(right.loc.start.line - left.loc.end.line - 1, 0);
+        }
+
         return {
             ImportDeclaration(node) {
                 if (!ignoreDeclarationSort) {
+                    if (
+                        previousDeclaration &&
+                        allowSeparatedGroups &&
+                        getNumberOfLinesBetween(previousDeclaration, node) > 0
+                    ) {
+
+                        // reset declaration sort
+                        previousDeclaration = null;
+                    }
+
                     if (previousDeclaration) {
                         const currentMemberSyntaxGroupIndex = getMemberParameterGroupIndex(node),
                             previousMemberSyntaxGroupIndex = getMemberParameterGroupIndex(previousDeclaration);

tests/lib/rules/sort-imports.js

@@ -101,7 +101,45 @@ ruleTester.run("sort-imports", rule, {
         },
 
         // https://github.com/eslint/eslint/issues/5305
-        "import React, {Component} from 'react';"
+        "import React, {Component} from 'react';",
+
+        // allowSeparatedGroups
+        {
+            code: "import b from 'b';\n\nimport a from 'a';",
+            options: [{ allowSeparatedGroups: true }]
+        },
+        {
+            code: "import a from 'a';\n\nimport 'b';",
+            options: [{ allowSeparatedGroups: true }]
+        },
+        {
+            code: "import { b } from 'b';\n\n\nimport { a } from 'a';",
+            options: [{ allowSeparatedGroups: true }]
+        },
+        {
+            code: "import b from 'b';\n// comment\nimport a from 'a';",
+            options: [{ allowSeparatedGroups: true }]
+        },
+        {
+            code: "import b from 'b';\nfoo();\nimport a from 'a';",
+            options: [{ allowSeparatedGroups: true }]
+        },
+        {
+            code: "import { b } from 'b';/*\n comment \n*/import { a } from 'a';",
+            options: [{ allowSeparatedGroups: true }]
+        },
+        {
+            code: "import b from\n'b';\n\nimport\n a from 'a';",
+            options: [{ allowSeparatedGroups: true }]
+        },
+        {
+            code: "import c from 'c';\n\nimport a from 'a';\nimport b from 'b';",
+            options: [{ allowSeparatedGroups: true }]
+        },
+        {
+            code: "import c from 'c';\n\nimport b from 'b';\n\nimport a from 'a';",
+            options: [{ allowSeparatedGroups: true }]
+        }
     ],
     invalid: [
         {
@@ -287,6 +325,125 @@ ruleTester.run("sort-imports", rule, {
                 data: { memberName: "qux" },
                 type: "ImportSpecifier"
             }]
+        },
+
+        // allowSeparatedGroups
+        {
+            code: "import b from 'b';\nimport a from 'a';",
+            output: null,
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import b from 'b';\nimport a from 'a';",
+            output: null,
+            options: [{}],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import b from 'b';\nimport a from 'a';",
+            output: null,
+            options: [{ allowSeparatedGroups: false }],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import b from 'b';import a from 'a';",
+            output: null,
+            options: [{ allowSeparatedGroups: false }],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import b from 'b'; /* comment */ import a from 'a';",
+            output: null,
+            options: [{ allowSeparatedGroups: false }],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import b from 'b'; // comment\nimport a from 'a';",
+            output: null,
+            options: [{ allowSeparatedGroups: false }],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import b from 'b'; // comment 1\n/* comment 2 */import a from 'a';",
+            output: null,
+            options: [{ allowSeparatedGroups: false }],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import { b } from 'b'; /* comment line 1 \n comment line 2 */ import { a } from 'a';",
+            output: null,
+            options: [{ allowSeparatedGroups: false }],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import b\nfrom 'b'; import a\nfrom 'a';",
+            output: null,
+            options: [{ allowSeparatedGroups: false }],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import { b } from \n'b'; /* comment */ import\n { a } from 'a';",
+            output: null,
+            options: [{ allowSeparatedGroups: false }],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import { b } from \n'b';\nimport\n { a } from 'a';",
+            output: null,
+            options: [{ allowSeparatedGroups: false }],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration"
+            }]
+        },
+        {
+            code: "import c from 'c';\n\nimport b from 'b';\nimport a from 'a';",
+            output: null,
+            options: [{ allowSeparatedGroups: true }],
+            errors: [{
+                messageId: "sortImportsAlphabetically",
+                type: "ImportDeclaration",
+                line: 4
+            }]
+        },
+        {
+            code: "import b from 'b';\n\nimport { c, a } from 'c';",
+            output: "import b from 'b';\n\nimport { a, c } from 'c';",
+            options: [{ allowSeparatedGroups: true }],
+            errors: [{
+                messageId: "sortMembersAlphabetically",
+                type: "ImportSpecifier"
+            }]
         }
     ]
 });