mirror of
https://github.com/luzhisheng/js_reverse.git
synced 2025-04-12 11:37:09 +08:00
AST操作之如何插入节点
需求:var a = 123;后面增加一个兄弟节点b = 111
const fs = require('fs');
const {parse} = require("@babel/parser");
const traverse = require("@babel/traverse").default;
const generator = require("@babel/generator").default;
const t = require('@babel/types');
let encode_file = "./encode.js";
let js_code = fs.readFileSync(encode_file, {encoding: "utf-8"});
let ast = parse(js_code, {
sourceType: 'module',
});
const visitor = {
VariableDeclarator(path) {
let {id} = path.node;
// 这里一定要判断准确,否则会无限循环
if(id.name == 'a'){
let new_id = t.Identifier("b");
let new_init = t.NumericLiteral(111);
let new_node = t.VariableDeclarator(new_id, new_init);
path.insertAfter(new_node)
}
},
};
traverse(ast, visitor);
// 将修改后的AST重新生成为代码
const modifiedCode = generator(ast).code;
console.log(modifiedCode);