feat(@angular/build): migrate Angular Linker to oxc-parser and magic-string

This refactors the Angular linker processing in the ESBuild pipeline to use `oxc-parser` and `magic-string` instead of `@babel/core`.

By using the lightweight AST and precise token spans provided by OXC, the linker is able to process partial declarations via targeted `magic-string` overwrites in-place. This removes the dependency on `@babel/core` and the linker Babel plugin, yielding faster build startup times and improved compilation performance.

Author: clydin

packages/angular/build/src/tools/angular/linker/oxc-ast-host.ts

@@ -0,0 +1,296 @@
+/**
+ * @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.dev/license
+ */
+
+import type { AstHost, Range } from '@angular/compiler-cli/linker';
+import { FatalLinkerError } from '@angular/compiler-cli/linker';
+import type {
+  ArrayExpression,
+  ArrowFunctionExpression,
+  BooleanLiteral,
+  CallExpression,
+  Function as FunctionNode,
+  Node,
+  NullLiteral,
+  NumericLiteral,
+  ObjectExpression,
+  StringLiteral,
+  UnaryExpression,
+} from '@oxc-project/types';
+
+function isNode(node: unknown): node is Node {
+  return typeof node === 'object' && node !== null && 'type' in node;
+}
+
+/**
+ * An implementation of `AstHost` that queries information from `oxc-parser` AST nodes.
+ */
+export class OxcAstHost implements AstHost<unknown> {
+  getSymbolName(node: unknown): string | null {
+    if (!isNode(node)) {
+      return null;
+    }
+
+    if (node.type === 'Identifier') {
+      return node.name;
+    } else if (node.type === 'MemberExpression') {
+      if (!node.computed && node.property.type === 'Identifier') {
+        return node.property.name;
+      }
+    }
+
+    return null;
+  }
+
+  isStringLiteral(node: unknown): node is StringLiteral {
+    return isNode(node) && node.type === 'Literal' && typeof node.value === 'string';
+  }
+
+  parseStringLiteral(str: unknown): string {
+    if (!this.isStringLiteral(str)) {
+      throw new FatalLinkerError(str as object, 'Unsupported syntax, expected a string literal.');
+    }
+
+    return str.value;
+  }
+
+  isNumericLiteral(node: unknown): node is NumericLiteral {
+    return isNode(node) && node.type === 'Literal' && typeof node.value === 'number';
+  }
+
+  parseNumericLiteral(num: unknown): number {
+    if (!this.isNumericLiteral(num)) {
+      throw new FatalLinkerError(num as object, 'Unsupported syntax, expected a numeric literal.');
+    }
+
+    return num.value;
+  }
+
+  isBooleanLiteral(node: unknown): node is BooleanLiteral | UnaryExpression {
+    if (!isNode(node)) {
+      return false;
+    }
+
+    return (
+      (node.type === 'Literal' && typeof node.value === 'boolean') || isMinifiedBooleanLiteral(node)
+    );
+  }
+
+  parseBooleanLiteral(bool: unknown): boolean {
+    if (isNode(bool)) {
+      if (bool.type === 'Literal' && typeof bool.value === 'boolean') {
+        return bool.value;
+      }
+      if (isMinifiedBooleanLiteral(bool)) {
+        return !bool.argument.value;
+      }
+    }
+
+    throw new FatalLinkerError(bool as object, 'Unsupported syntax, expected a boolean literal.');
+  }
+
+  isNull(node: unknown): node is NullLiteral {
+    return isNode(node) && node.type === 'Literal' && node.value === null;
+  }
+
+  isArrayLiteral(node: unknown): node is ArrayExpression {
+    return isNode(node) && node.type === 'ArrayExpression';
+  }
+
+  parseArrayLiteral(array: unknown): unknown[] {
+    if (!this.isArrayLiteral(array)) {
+      throw new FatalLinkerError(array as object, 'Unsupported syntax, expected an array literal.');
+    }
+
+    const result: unknown[] = [];
+
+    for (const element of array.elements) {
+      if (element === null) {
+        throw new FatalLinkerError(
+          array as object,
+          'Unsupported syntax, element in array not to be empty.',
+        );
+      }
+      if (element.type === 'SpreadElement') {
+        throw new FatalLinkerError(
+          element as object,
+          'Unsupported syntax, element in array not to use spread syntax.',
+        );
+      }
+      result.push(element);
+    }
+
+    return result;
+  }
+
+  isObjectLiteral(node: unknown): node is ObjectExpression {
+    return isNode(node) && node.type === 'ObjectExpression';
+  }
+
+  parseObjectLiteral(obj: unknown): Map<string, unknown> {
+    if (!this.isObjectLiteral(obj)) {
+      throw new FatalLinkerError(obj as object, 'Unsupported syntax, expected an object literal.');
+    }
+
+    const result = new Map<string, unknown>();
+
+    for (const property of obj.properties) {
+      if (property.type !== 'Property') {
+        throw new FatalLinkerError(
+          property as object,
+          'Unsupported syntax, expected a property assignment.',
+        );
+      }
+
+      const keyNode = property.key;
+
+      let key: string;
+      if (keyNode.type === 'Identifier') {
+        key = keyNode.name;
+      } else if (this.isStringLiteral(keyNode)) {
+        key = keyNode.value;
+      } else if (this.isNumericLiteral(keyNode)) {
+        key = String(keyNode.value);
+      } else {
+        throw new FatalLinkerError(
+          keyNode as object,
+          'Unsupported syntax, expected a property name.',
+        );
+      }
+
+      result.set(key, property.value);
+    }
+
+    return result;
+  }
+
+  isFunctionExpression(node: unknown): node is FunctionNode | ArrowFunctionExpression {
+    if (!isNode(node)) {
+      return false;
+    }
+
+    return (
+      node.type === 'FunctionDeclaration' ||
+      node.type === 'FunctionExpression' ||
+      node.type === 'ArrowFunctionExpression'
+    );
+  }
+
+  parseReturnValue(fn: unknown): unknown {
+    if (!this.isFunctionExpression(fn)) {
+      throw new FatalLinkerError(fn as object, 'Unsupported syntax, expected a function.');
+    }
+
+    const body = fn.body;
+    if (!body || !isNode(body)) {
+      throw new FatalLinkerError(fn as object, 'Unsupported syntax, expected a function body.');
+    }
+
+    if (body.type !== 'BlockStatement') {
+      return body;
+    }
+
+    const statements = body.body;
+    if (statements.length !== 1) {
+      throw new FatalLinkerError(
+        body as object,
+        'Unsupported syntax, expected a function body with a single return statement.',
+      );
+    }
+
+    const stmt = statements[0];
+    if (stmt.type !== 'ReturnStatement') {
+      throw new FatalLinkerError(
+        stmt as object,
+        'Unsupported syntax, expected a function body with a single return statement.',
+      );
+    }
+
+    if (!stmt.argument) {
+      throw new FatalLinkerError(
+        stmt as object,
+        'Unsupported syntax, expected function to return a value.',
+      );
+    }
+
+    return stmt.argument;
+  }
+
+  parseParameters(fn: unknown): unknown[] {
+    if (!this.isFunctionExpression(fn)) {
+      throw new FatalLinkerError(fn as object, 'Unsupported syntax, expected a function.');
+    }
+
+    return fn.params;
+  }
+
+  isCallExpression(node: unknown): node is CallExpression {
+    return isNode(node) && node.type === 'CallExpression';
+  }
+
+  parseCallee(call: unknown): unknown {
+    if (!this.isCallExpression(call)) {
+      throw new FatalLinkerError(call as object, 'Unsupported syntax, expected a call expression.');
+    }
+
+    return call.callee;
+  }
+
+  parseArguments(call: unknown): unknown[] {
+    if (!this.isCallExpression(call)) {
+      throw new FatalLinkerError(call as object, 'Unsupported syntax, expected a call expression.');
+    }
+
+    const result: unknown[] = [];
+
+    for (const arg of call.arguments) {
+      if (arg.type === 'SpreadElement') {
+        throw new FatalLinkerError(
+          arg as object,
+          'Unsupported syntax, argument not to use spread syntax.',
+        );
+      }
+      result.push(arg);
+    }
+
+    return result;
+  }
+
+  getRange(node: unknown): Range {
+    if (!isNode(node) || typeof node.start !== 'number' || typeof node.end !== 'number') {
+      throw new FatalLinkerError(
+        node as object,
+        'Unable to read range for node - it is missing location information.',
+      );
+    }
+
+    return {
+      startPos: node.start,
+      startLine: 0,
+      startCol: 0,
+      endPos: node.end,
+    };
+  }
+}
+
+function isMinifiedBooleanLiteral(
+  node: Node,
+): node is UnaryExpression & { argument: NumericLiteral } {
+  if (node.type !== 'UnaryExpression') {
+    return false;
+  }
+
+  const arg = node.argument;
+
+  return (
+    node.prefix === true &&
+    node.operator === '!' &&
+    arg.type === 'Literal' &&
+    typeof arg.value === 'number' &&
+    (arg.value === 0 || arg.value === 1)
+  );
+}