《TypeScript高级编程》6.3 重构工具与 codemod

import * as ts from "typescript";

const config: ts.CompilerOptions = { target: ts.ScriptTarget.ES2022 };

const host: ts.LanguageServiceHost = {
  getScriptFileNames: () => ["/work/src/index.ts", "/work/src/util.ts"],
  getScriptVersion: () => "1",
  getScriptSnapshot: (fileName) => {
    const text = ts.sys.readFile(fileName);
    return text === undefined ? undefined : ts.ScriptSnapshot.fromString(text);
  },
  getCurrentDirectory: () => "/work",
  getCompilationSettings: () => config,
  getDefaultLibFileName: (options) => ts.getDefaultLibFilePath(options),
  fileExists: ts.sys.fileExists,
  readFile: ts.sys.readFile,
  readDirectory: ts.sys.readDirectory,
  directoryExists: ts.sys.directoryExists,
  getDirectories: ts.sys.getDirectories,
};

const service = ts.createLanguageService(host);
const file = "/work/src/index.ts";
const program = service.getProgram()!;
const source = program.getSourceFile(file)!;

const position = source.getPositionOfLineAndCharacter(2, 13);
const spans = service.findRenameLocations(file, position, false, false, false) ?? [];

for (const span of spans) {
  const sf = program.getSourceFile(span.fileName)!;
  const old = sf.text.slice(span.textSpan.start, span.textSpan.start + span.textSpan.length);
  console.log(`${span.fileName}:${old} -> newName`);
}

const key = "getUserInfo"; // 字符串，不会被改
// getUserInfo 是老名字     // 注释，不会被改

import { Project } from "ts-morph";

const project = new Project({ tsConfigFilePath: "tsconfig.json" });

const fn = project.getSourceFileOrThrow("src/index.ts").getFunctionOrThrow("greet");

fn.rename("sayHello");                 // 语义重命名，跨文件生效
fn.setIsExported(true);                // 补上 export
fn.getParameterOrThrow("name").setType("string");
fn.addParameter({ name: "loud", type: "boolean", initializer: "false" });

project.saveSync();                    // 只写「脏」文件，没改的一个字节都不动

const refs = fn.findReferences();

for (const ref of refs) {
  for (const entry of ref.getReferences()) {
    const node = entry.getNode();
    console.log(`${node.getSourceFile().getFilePath()}:${node.getStartLineNumber()}`);
  }
}

/work/src/index.ts:12
/work/src/api/handler.ts:34
/work/src/api/handler.ts:51
/work/src/cli.ts:8

import { Project } from "ts-morph";

const project = new Project({ tsConfigFilePath: "tsconfig.json" });

for (const source of project.getSourceFiles()) {
  for (const en of source.getEnums()) {
    const name = en.getName();

    const members = en.getMembers().map((member) => {
      const key = member.getName();
      const value = member.getInitializer()?.getText() ?? JSON.stringify(key);
      return `  ${key}: ${value},`;
    });

    const literal = [
      `const ${name} = {`,
      ...members,
      `} as const;`,
      `type ${name} = (typeof ${name})[keyof typeof ${name}];`,
    ].join("\n");

    en.replaceWithText(literal);
  }
}

project.saveSync();

enum Color {
  Red = "red",
  Green = "green",
}

function paint(c: Color): string {
  return c;
}

const Color = {
  Red: "red",
  Green: "green",
} as const;
type Color = (typeof Color)[keyof typeof Color];

function paint(c: Color): string {
  return c;
}

# 1) 跑完后统一格式，让「格式差异」与「语义差异」分开成两次提交
npx prettier --write "src/**/*.ts"

# 2) 先 dry-run 看会改哪些文件，确认改动面符合预期
npx tsx codemod.ts --dry-run

# 3) 只看统计，快速判断有没有失控
git diff --stat | tail -3

import { InMemoryFileSystemHost, Project } from "ts-morph";

const project = new Project({
  tsConfigFilePath: "tsconfig.json",
  fileSystem: new InMemoryFileSystemHost(),
});

// ……执行改写逻辑

for (const file of project.getSourceFiles()) {
  if (file.isSaved()) continue;      // 没被改过的跳过
  console.log(`--- ${file.getFilePath()}`);
  console.log(file.getFullText());
}

# 前置：工作区必须干净，否则回滚会把你的未提交改动一起冲掉
test -z "$(git status --porcelain)" || { echo "工作区不干净，先提交"; exit 1; }

npx tsx codemod.ts
npx tsc --noEmit                       # 类型必须仍然通过
npx tsx codemod.ts                     # 幂等断言：这次应当零 diff
test -z "$(git status --porcelain)" || { echo "不幂等，请检查"; exit 1; }