babel

babel 是一个JavaScript 编译器。

@babel/core

babel 核心包，包含各种 transform 方法。

@babel/parser

负责解析代码成为 ast 语法树🌲astexplorer (opens new window)。

Heavily based on acorn and acorn-jsx.

@babel/traverse

遍历 node types 节点。

import * as parser from "@babel/parser";
import traverse from "@babel/traverse";

const code = `function square(n) {
  return n * n;
}`;

const ast = parser.parse(code);

traverse(ast, {
  // 方式1
  enter(path) {
    if (path.isIdentifier({ name: "n" })) {
      path.node.name = "x";
    }
  },
  // 方式2
  FunctionDeclaration: function(path) {
    path.node.id.name = "x";
  },
});

@babel/generator

Turns an AST into code.

import { parse } from "@babel/parser";
import generate from "@babel/generator";

const code = "class Example {}";
const ast = parse(code);

const output = generate(
  ast,
  {
    /* options */
  },
  code
);

@babel/types

This module contains methods for building ASTs manually and for checking the types of AST nodes.

参考

babel (opens new window)
babel 中文文档 (opens new window)