Add new rule: grouped-imports

src/configs/all.ts

@@ -181,6 +181,7 @@ export const rules = {
     // "file-header": No sensible default
     "deprecation": true,
     "encoding": true,
+    "grouped-imports": true,
     "import-spacing": true,
     "interface-name": true,
     "interface-over-type-literal": true,

src/configs/latest.ts

@@ -42,6 +42,7 @@ export const rules = {
         "check-parameters",
     ],
     "no-this-assignment": true,
+    "grouped-imports": true,
 };
 // tslint:enable object-literal-sort-keys
 

src/rules/groupedImportsRule.ts

@@ -0,0 +1,152 @@
+/**
+ * @license
+ * Copyright 2017 Palantir Technologies, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as Lint from "tslint";
+import { isImportDeclaration } from "tsutils";
+import * as ts from "typescript";
+
+export class Rule extends Lint.Rules.AbstractRule {
+    /* tslint:disable:object-literal-sort-keys */
+    public static metadata: Lint.IRuleMetadata = {
+        ruleName: "grouped-imports",
+        description: "Separate import groups by blank lines.",
+        rationale: "Keeps a clear overview on dependencies.",
+        optionsDescription: "Not configurable.",
+        hasFix: true,
+        options: {},
+        optionExamples: [true],
+        type: "style",
+        typescriptOnly: false,
+    };
+    /* tslint:enable:object-literal-sort-keys */
+
+    public static IMPORT_SOURCES_SEPARATED = "Import sources within a group must not be separated by blank lines";
+    public static IMPORT_SOURCES_NOT_SEPARATED =
+        "Import sources of different groups must be separated by a single blank line";
+    public static IMPORT_SOURCES_ORDER =
+        "Import sources of different groups must be sorted by: libraries, parent directories, current directory";
+
+    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
+        return this.applyWithWalker(new Walker(sourceFile, this.ruleName, this.getOptions()));
+    }
+}
+
+enum ImportStatementType {
+    LIBRARY_IMPORT = 1,
+    PARENT_DIRECTORY_IMPORT = 2,
+    CURRENT_DIRECTORY_IMPORT = 3,
+}
+
+interface ImportStatement {
+    statement: ts.Statement;
+    type: ImportStatementType;
+    lineStart: number;
+    lineEnd: number;
+}
+
+class Walker extends Lint.AbstractWalker<Lint.IOptions> {
+    private lastImportStatement: ImportStatement;
+
+    private static getImportStatementType(statement: ts.Statement): ImportStatementType {
+        const path = Walker.getImportPath(statement);
+        if (path.charAt(0) === ".") {
+            if (path.charAt(1) === ".") {
+                return ImportStatementType.PARENT_DIRECTORY_IMPORT;
+            } else {
+                return ImportStatementType.CURRENT_DIRECTORY_IMPORT;
+            }
+        } else {
+            return ImportStatementType.LIBRARY_IMPORT;
+        }
+    }
+
+    private static getImportPath(statement: ts.Statement): string {
+        const str = statement.getText();
+        let index;
+        let lastIndex;
+        index = str.indexOf("'");
+        if (index > 0) {
+            lastIndex = str.lastIndexOf("'");
+        } else {
+            index = str.indexOf("\"");
+            lastIndex = str.lastIndexOf("\"");
+        }
+        if (index < 0 || lastIndex < 0) {
+            throw new Error(`Unable to extract path from import statement \`${statement.getText()}\``);
+        }
+        return str.substring(index + 1, lastIndex);
+    }
+
+    public walk(sourceFile: ts.SourceFile): void {
+        sourceFile.statements
+            .filter(isImportDeclaration)
+            .forEach((st) => this.checkStatement(st));
+    }
+
+    private toImportStatement(statement: ts.Statement): ImportStatement {
+        return {
+            lineEnd: this.sourceFile.getLineAndCharacterOfPosition(statement.getEnd()).line,
+            lineStart: this.sourceFile.getLineAndCharacterOfPosition(statement.getStart()).line,
+            statement,
+            type: Walker.getImportStatementType(statement),
+        };
+    }
+
+    private checkStatement(statement: ts.Statement): void {
+        const importStatement = this.toImportStatement(statement);
+        if (this.lastImportStatement) {
+            this.checkImportStatement(importStatement);
+        }
+        this.lastImportStatement = importStatement;
+    }
+
+    private checkImportStatement(importStatement: ImportStatement) {
+        if (importStatement.type === this.lastImportStatement.type) {
+            if (importStatement.lineStart !== this.lastImportStatement.lineEnd + 1) {
+                const replacement = Lint.Replacement.deleteFromTo(
+                    this.lastImportStatement.statement.getEnd() + 1, importStatement.statement.getStart());
+                this.addFailureAtNode(importStatement.statement, Rule.IMPORT_SOURCES_SEPARATED, replacement);
+            }
+        } else if (importStatement.type.valueOf() < this.lastImportStatement.type.valueOf()) {
+            this.addFailureAtNode(importStatement.statement, Rule.IMPORT_SOURCES_ORDER, this.getAllImportsFix());
+        } else {
+            if (importStatement.lineStart !== this.lastImportStatement.lineEnd + 2) {
+                const replacement = Lint.Replacement.appendText(importStatement.statement.getStart(), ts.sys.newLine);
+                this.addFailureAtNode(importStatement.statement, Rule.IMPORT_SOURCES_NOT_SEPARATED, replacement);
+            }
+        }
+    }
+
+    private getAllImportsFix(): Lint.Fix {
+        const importStatements = this.sourceFile.statements.filter(isImportDeclaration);
+        const libs = importStatements.filter((st) => Walker.getImportStatementType(st) === ImportStatementType.LIBRARY_IMPORT);
+        const parent = importStatements.filter((st) => Walker.getImportStatementType(st) === ImportStatementType.PARENT_DIRECTORY_IMPORT);
+        const current = importStatements.filter((st) => Walker.getImportStatementType(st) === ImportStatementType.CURRENT_DIRECTORY_IMPORT);
+        let imports: string[] = [];
+        [libs, parent, current].forEach((statements) => {
+            if (statements.length) {
+                imports = imports.concat(statements.map((st) => st.getText()));
+                imports.push("");
+            }
+        });
+        return Lint.Replacement.replaceFromTo(
+            importStatements[0].getStart(),
+            importStatements[importStatements.length - 1].getEnd(),
+            imports.join(ts.sys.newLine),
+        );
+    }
+}

test/rules/grouped-imports/bad-order.ts.fix

@@ -0,0 +1,6 @@
+import {foo} from 'foo';
+
+import {bar} from '../bar';
+
+import './baz';
+

test/rules/grouped-imports/bad-order.ts.lint

@@ -0,0 +1,6 @@
+import {bar} from '../bar';
+
+import {foo} from 'foo';
+~~~~~~~~~~~~~~~~~~~~~~~~ [Import sources of different groups must be sorted by: libraries, parent directories, current directory]
+
+import './baz';

test/rules/grouped-imports/different-groups.ts.fix

@@ -0,0 +1,3 @@
+import {foo} from 'foo';
+
+import {bar} from '../bar';

test/rules/grouped-imports/different-groups.ts.lint

@@ -0,0 +1,3 @@
+import {foo} from 'foo';
+import {bar} from '../bar';
+~~~~~~~~~~~~~~~~~~~~~~~~~~~ [Import sources of different groups must be separated by a single blank line]

test/rules/grouped-imports/same-group.ts.fix

@@ -0,0 +1,2 @@
+import {foo} from 'foo';
+import {bar} from 'bar';

test/rules/grouped-imports/same-group.ts.lint

@@ -0,0 +1,4 @@
+import {foo} from 'foo';
+
+import {bar} from 'bar';
+~~~~~~~~~~~~~~~~~~~~~~~~ [Import sources within a group must not be separated by blank lines]

test/rules/grouped-imports/tslint.json

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "grouped-imports": true
+  }
+}