(fix) indentation of organize imports (#890)

Use indentation of first line of imports to determine the indentation of the following lines
#854

Author: dummdidumm

packages/language-server/src/plugins/typescript/features/CodeActionsProvider.ts

@@ -8,8 +8,14 @@ import {
     VersionedTextDocumentIdentifier,
     WorkspaceEdit
 } from 'vscode-languageserver';
-import { Document, mapRangeToOriginal, isRangeInTag, isInTag } from '../../../lib/documents';
-import { pathToUrl, flatten, isNotNullOrUndefined } from '../../../utils';
+import {
+    Document,
+    mapRangeToOriginal,
+    isRangeInTag,
+    isInTag,
+    getLineAtPosition
+} from '../../../lib/documents';
+import { pathToUrl, flatten, isNotNullOrUndefined, modifyLines } from '../../../utils';
 import { CodeActionsProvider } from '../../interfaces';
 import { SnapshotFragment, SvelteSnapshotFragment } from '../DocumentSnapshot';
 import { LSAndTSDocResolver } from '../LSAndTSDocResolver';
@@ -84,7 +90,10 @@ export class CodeActionsProviderImpl implements CodeActionsProvider {
                             mapRangeToOriginal(fragment, convertRange(fragment, edit.span))
                         );
 
-                        return TextEdit.replace(range, edit.newText);
+                        return TextEdit.replace(
+                            range,
+                            this.fixIndentationOfImports(edit.newText, range, document)
+                        );
                     })
                 );
             })
@@ -99,6 +108,22 @@ export class CodeActionsProviderImpl implements CodeActionsProvider {
         ];
     }
 
+    private fixIndentationOfImports(edit: string, range: Range, document: Document): string {
+        // "Organize Imports" will have edits that delete all imports by return empty edits
+        // and one edit which contains all the organized imports. Fix indentation
+        // of that one by prepending all lines with the indentation of the first line.
+        if (!edit || range.start.character === 0) {
+            return edit;
+        }
+
+        const line = getLineAtPosition(range.start, document.getText());
+        const leadingChars = line.substring(0, range.start.character);
+        if (leadingChars.trim() !== '') {
+            return edit;
+        }
+        return modifyLines(edit, (line, idx) => (idx === 0 || !line ? line : leadingChars + line));
+    }
+
     private checkRemoveImportCodeActionRange(
         edit: ts.TextChange,
         fragment: SnapshotFragment,

packages/language-server/src/utils.ts

@@ -107,3 +107,22 @@ export function getRegExpMatches(regex: RegExp, str: string) {
     }
     return matches;
 }
+
+/**
+ * Function to modify each line of a text, preserving the line break style (`\n` or `\r\n`)
+ */
+export function modifyLines(
+    text: string,
+    replacementFn: (line: string, lineIdx: number) => string
+): string {
+    let idx = 0;
+    return text
+        .split('\r\n')
+        .map((l1) =>
+            l1
+                .split('\n')
+                .map((line) => replacementFn(line, idx++))
+                .join('\n')
+        )
+        .join('\r\n');
+}

packages/language-server/test/plugins/typescript/features/CodeActionsProvider.test.ts

@@ -264,7 +264,7 @@ describe('CodeActionsProvider', () => {
                             edits: [
                                 {
                                     // eslint-disable-next-line max-len
-                                    newText: "import A from './A';\nimport { c } from './c';\n",
+                                    newText: "import A from './A';\n  import { c } from './c';\n",
                                     range: {
                                         start: {
                                             line: 1,
@@ -339,7 +339,7 @@ describe('CodeActionsProvider', () => {
                             edits: [
                                 {
                                     newText:
-                                        "import { _,_d } from 'svelte-i18n';\nimport { _e } from 'svelte-i18n1';\n",
+                                        "import { _,_d } from 'svelte-i18n';\n  import { _e } from 'svelte-i18n1';\n",
                                     range: {
                                         end: {
                                             character: 0,

packages/language-server/test/utils.test.ts

@@ -1,4 +1,4 @@
-import { isBeforeOrEqualToPosition, regexLastIndexOf } from '../src/utils';
+import { isBeforeOrEqualToPosition, modifyLines, regexLastIndexOf } from '../src/utils';
 import { Position } from 'vscode-languageserver';
 import * as assert from 'assert';
 
@@ -43,4 +43,22 @@ describe('utils', () => {
             assert.equal(regexLastIndexOf('<bla blubb={() => hello', /[\W\s]/g), 17);
         });
     });
+
+    describe('#modifyLines', () => {
+        it('should work', () => {
+            assert.equal(
+                modifyLines('a\nb\r\nc\nd', (line) => 1 + line),
+                '1a\n1b\r\n1c\n1d'
+            );
+        });
+
+        it('should pass correct line numbers', () => {
+            const idxs: number[] = [];
+            modifyLines('a\nb\r\nc\nd', (_, idx) => {
+                idxs.push(idx);
+                return _;
+            });
+            assert.deepStrictEqual(idxs, [0, 1, 2, 3]);
+        });
+    });
 });