十一.seal

1.转换箭头函数

//是babel的核心库
let babel = require("@babel/core")
//生成节点
let t = require("babel-types")

let code = `const sum=(a,b)+>a+b`
let transformArrayFunction = {
  //访问器模式 访问者
  visitor: {
    ArrayFunctionExpression: (path, state) => {
      let node = path.node //拿到路径里的节点
      let id = path.parent.id //path.parent父节点的意思
      let params = node.params
      //   let body = node.body;//BinaryExprssion
      let body = t.blockStatement([t.returnStatement(node.body)])
      let functionDeclaration = t.functionDeclaration(
        id,
        params,
        body,
        false,
        false
      )
      path.parentath.replaceWith(functionDeclaration)
    },
  },
}
let result = babel.transform(core, {
  plugins: [transformArrayFunction],
})
console.log(result.code)
console.log("result", result)

2.把类转换

let transformArrowFunctions = {
  visitor: {
    ClassDeclaration: (path, state) => {
      let node = path.node;
      let id = node.id;
      let methods = node.body.body;
      let functions = [];
      methods.forEach(function(method) {
        if (method.kind == "constructor") {
          let func = t.functionDeclaration(
            id,
            method.params,
            method.body,
            false,
            false
          );
        } else {let memberExpression=t.memberExpression(t.memberExpression(id,t.identifier('protype'))
          let memberFunciton = t.functionDeclaration(
            null,
            method.params,
            method.body,
            false,
            false
          );
          t.assignmentExpression("=", memberExpression, memberFunciton);
          statment.push(assignmentExpression);
        }
      });
    }
  }
};