refactor(migrations): add common helpers for inserting TODOs (angular#57898)

devversion · pkozlowski-opensource · commit 5bb7050c59b6 · 2024-09-23T12:41:34.000+02:00
Adds a common helper for inserting TODOs to Tsurge. PR Close angular#57898
diff --git a/packages/core/schematics/ng-generate/inject-migration/BUILD.bazel b/packages/core/schematics/ng-generate/inject-migration/BUILD.bazel
@@ -19,6 +19,7 @@ ts_library(
     tsconfig = "//packages/core/schematics:tsconfig.json",
     deps = [
         "//packages/core/schematics/utils",
+        "//packages/core/schematics/utils/tsurge",
         "@npm//@angular-devkit/schematics",
         "@npm//@types/node",
         "@npm//typescript",
diff --git a/packages/core/schematics/ng-generate/inject-migration/analysis.ts b/packages/core/schematics/ng-generate/inject-migration/analysis.ts
@@ -223,29 +223,6 @@ export function getSuperParameters(
   return usedParams;
 }
 
-/**
- * Gets the indentation text of a node. Can be used to
- * output text with the same level of indentation.
- * @param node Node for which to get the indentation level.
- */
-export function getNodeIndentation(node: ts.Node): string {
-  const fullText = node.getFullText();
-  const end = fullText.indexOf(node.getText());
-  let result = '';
-
-  for (let i = end - 1; i > -1; i--) {
-    // Note: LF line endings are `\n` while CRLF are `\r\n`. This logic should cover both, because
-    // we start from the beginning of the node and go backwards so will always hit `\n` first.
-    if (fullText[i] !== '\n') {
-      result = fullText[i] + result;
-    } else {
-      break;
-    }
-  }
-
-  return result;
-}
-
 /** Checks whether a parameter node declares a property on its class. */
 export function parameterDeclaresProperty(node: ts.ParameterDeclaration): boolean {
   return !!node.modifiers?.some(
diff --git a/packages/core/schematics/ng-generate/inject-migration/migration.ts b/packages/core/schematics/ng-generate/inject-migration/migration.ts
@@ -10,7 +10,6 @@ import ts from 'typescript';
 import {PendingChange, ChangeTracker} from '../../utils/change_tracker';
 import {
   analyzeFile,
-  getNodeIndentation,
   getSuperParameters,
   getConstructorUnusedParameters,
   hasGenerics,
@@ -22,6 +21,7 @@ import {getAngularDecorators} from '../../utils/ng_decorators';
 import {getImportOfIdentifier} from '../../utils/typescript/imports';
 import {closestNode} from '../../utils/typescript/nodes';
 import {findUninitializedPropertiesToCombine} from './internal';
+import {getLeadingLineWhitespaceOfNode} from '../../utils/tsurge/helpers/ast/leading_space';
 
 /**
  * Placeholder used to represent expressions inside the AST.
@@ -173,13 +173,13 @@ function migrateClass(
   const superParameters = superCall
     ? getSuperParameters(constructor, superCall, localTypeChecker)
     : null;
-  const memberIndentation = getNodeIndentation(node.members[0]);
+  const memberIndentation = getLeadingLineWhitespaceOfNode(node.members[0]);
   const removedStatementCount = removedStatements?.size || 0;
   const innerReference =
     superCall ||
     constructor.body?.statements.find((statement) => !removedStatements?.has(statement)) ||
     constructor;
-  const innerIndentation = getNodeIndentation(innerReference);
+  const innerIndentation = getLeadingLineWhitespaceOfNode(innerReference);
   const propsToAdd: string[] = [];
   const prependToConstructor: string[] = [];
   const afterSuper: string[] = [];
diff --git a/packages/core/schematics/utils/tsurge/helpers/ast/insert_preceding_line.ts b/packages/core/schematics/utils/tsurge/helpers/ast/insert_preceding_line.ts
@@ -0,0 +1,33 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import ts from 'typescript';
+import {Replacement, TextUpdate} from '../../replacement';
+import {getLeadingLineWhitespaceOfNode} from './leading_space';
+import {ProgramInfo} from '../../program_info';
+import {projectFile} from '../../project_paths';
+
+/**
+ * Inserts a leading single-line TODO for the given node,
+ * returning a replacement.
+ */
+export function insertPrecedingLine(
+  node: ts.Node,
+  info: ProgramInfo,
+  todoText: string,
+): Replacement {
+  const leadingSpace = getLeadingLineWhitespaceOfNode(node);
+  return new Replacement(
+    projectFile(node.getSourceFile(), info),
+    new TextUpdate({
+      position: node.getStart(),
+      end: node.getStart(),
+      toInsert: `${todoText}\n${leadingSpace}`,
+    }),
+  );
+}
diff --git a/packages/core/schematics/utils/tsurge/helpers/ast/leading_space.ts b/packages/core/schematics/utils/tsurge/helpers/ast/leading_space.ts
@@ -0,0 +1,31 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import ts from 'typescript';
+
+/**
+ * Gets the leading line whitespace of a given node.
+ *
+ * Useful for inserting e.g. TODOs without breaking indentation.
+ */
+export function getLeadingLineWhitespaceOfNode(node: ts.Node): string {
+  const fullText = node.getFullText().substring(0, node.getStart() - node.getFullStart());
+  let result = '';
+
+  for (let i = fullText.length - 1; i > -1; i--) {
+    // Note: LF line endings are `\n` while CRLF are `\r\n`. This logic should cover both, because
+    // we start from the beginning of the node and go backwards so will always hit `\n` first.
+    if (fullText[i] !== '\n') {
+      result = fullText[i] + result;
+    } else {
+      break;
+    }
+  }
+
+  return result;
+}
