babel 常用操作

• astexplorer
• babel-types

code to ast

const { parse } = babel;

const code = `
  for (let k in ${data}) {
     let ${path.__cxt} = _setCxt(k, ${data});
  }
`;
const ast = parse(code);

ast to code

const { default: generate } = require("@babel/generator");
const { code } = generate(path.node);

在顶层添加静态函数

function _setCxt(k, data) {
}

// https://babeljs.io/docs/en/babel-traverse
traverse(state.file.ast, {
  Program(path) {
    path.unshiftContainer("body", parse(`${_setCxt}`).program.body[0]);
  }
});

// or

export default function (babel) {
  return {
    visitor: {
      Program: {
        enter(path) {
         path.unshiftContainer("body", parse(`${_setCxt}`).program.body[0]);
        }
      }
    }
  };
}

获取父节点

path.parent; // node
path.parentPath // path

// 返回true则返回查找到的parent，可以返回false来遍历父节点。
path.findParent(pPath => {
 return true;
})

path类型判断

path.type === "Identifier";
path.isIdentifier();

用另一个替换当前节点

const { types: t } = babel;

// replaceWith(replacement: Node | NodePath): void;
path.replaceWith(t.Identifier("a"));

删除path

path.remove()