TypeScript编译器:如何从CallExpression中获取原始函数的FunctionDeclaration？

import * as ts from 'typescript';

const code = `function add(a: number, b: number): number {
  return a + b;
}

add(1, 2);`;

const sourceFile = ts.createSourceFile('example.ts', code, ts.ScriptTarget.ESNext, true);

function visit(node: ts.Node) {
  if (ts.isCallExpression(node)) {
    // 处理CallExpression节点
    const functionName = node.expression.getText();
    console.log('Function Name:', functionName);
    
    // 获取原始函数的FunctionDeclaration
    const functionDeclaration = findFunctionDeclaration(node.expression, sourceFile);
    console.log('Function Declaration:', functionDeclaration.getText());
  }

  ts.forEachChild(node, visit);
}

visit(sourceFile);

function findFunctionDeclaration(expression: ts.Expression, sourceFile: ts.SourceFile): ts.FunctionDeclaration | undefined {
  if (ts.isIdentifier(expression)) {
    const functionName = expression.getText();
    const functionDeclaration = sourceFile.statements.find((node) => {
      return ts.isFunctionDeclaration(node) && node.name && node.name.getText() === functionName;
    }) as ts.FunctionDeclaration;
    return functionDeclaration;
  }
  return undefined;
}