11.AST操作之删除节点-pop-delete-remove

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aiyingfeng 2023-08-22 11:01:01 +08:00
parent 3bf8d29b1e
commit 0871cb074f
8 changed files with 148 additions and 21 deletions

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# AST操作之删除节点
需求:还原十六进制字符串,比如需要处理的这样一个字串
```javascript
var a = "\x31\x32\x33\x34\x35\x36";
```
这里可以看到raw字段显示的是十六进制字符串
![debugger](./img/1.png)
删除raw字段就恢复十进制字符串
```javascript
const fs = require('fs');
const {parse} = require("@babel/parser");
const traverse = require("@babel/traverse").default;
const generator = require("@babel/generator").default;
let encode_file = "./encode.js";
let js_code = fs.readFileSync(encode_file, {encoding: "utf-8"});
let ast = parse(js_code, {
sourceType: 'module',
});
const visitor = {
StringLiteral(path) {
// 删除多余字段
delete path.node.extra.raw;
},
};
traverse(ast, visitor);
// 将修改后的AST重新生成为代码
const modifiedCode = generator(ast).code;
console.log(modifiedCode);
```
需求:将`var a = "123", b = 123;`中的`a = "123"`删除
```javascript
const fs = require('fs');
const {parse} = require("@babel/parser");
const traverse = require("@babel/traverse").default;
const generator = require("@babel/generator").default;
let encode_file = "./encode1.js";
let js_code = fs.readFileSync(encode_file, {encoding: "utf-8"});
let ast = parse(js_code, {
sourceType: 'module',
});
const visitor = {
VariableDeclarator(path) {
let init = path.get('init')
if(init.isStringLiteral()){
// 判断将整个节点删除
path.remove()
}
},
};
traverse(ast, visitor);
// 将修改后的AST重新生成为代码
const modifiedCode = generator(ast).code;
console.log(modifiedCode);
```
需求:将如下代码中的`crack();`删除
```javascript
function test(){
var a = 123;
c = a + b;
crack();
}
```
实现代码
```javascript
const fs = require('fs');
const {parse} = require("@babel/parser");
const traverse = require("@babel/traverse").default;
const generator = require("@babel/generator").default;
let encode_file = "./encode2.js";
let js_code = fs.readFileSync(encode_file, {encoding: "utf-8"});
let ast = parse(js_code, {
sourceType: 'module',
});
const visitor = {
BlockStatement(path) {
// path.node.body 是直接访问当前节点的 body 属性的值,返回一个数组(通常是一组语句节点)。
// path.get('body') 是通过路径对象的方法获取当前节点的 body 属性的子路径,你可以在这个子路径上进行更多的操作。
let body = path.node.body;
console.log(body);
body.pop()
},
};
traverse(ast, visitor);
// 将修改后的AST重新生成为代码
const modifiedCode = generator(ast).code;
console.log(modifiedCode);
```

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# AST操作之删除节点
需求还原十六进制字符串,比如需要处理的这样一个字串:
```javascript
var a = "\x31\x32\x33\x34\x35\x36";
```
这里可以看到raw字段显示的是十六进制字符串
![debugger](./img/1.png)
删除raw字段就恢复十进制字符串
```javascript
const fs = require('fs');
const {parse} = require("@babel/parser");
const traverse = require("@babel/traverse").default;
const generator = require("@babel/generator").default;
let encode_file = "./encode.js";
let encode_file = "./encode1.js";
let js_code = fs.readFileSync(encode_file, {encoding: "utf-8"});
let ast = parse(js_code, {
sourceType: 'module',
});
const visitor = {
StringLiteral(path) {
delete path.node.extra.raw;
VariableDeclarator(path) {
let init = path.get('init')
if(init.isStringLiteral()){
path.remove()
}
},
};
@ -35,5 +22,4 @@ traverse(ast, visitor);
// 将修改后的AST重新生成为代码
const modifiedCode = generator(ast).code;
console.log(modifiedCode);
```
console.log(modifiedCode);

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const fs = require('fs');
const {parse} = require("@babel/parser");
const traverse = require("@babel/traverse").default;
const generator = require("@babel/generator").default;
let encode_file = "./encode2.js";
let js_code = fs.readFileSync(encode_file, {encoding: "utf-8"});
let ast = parse(js_code, {
sourceType: 'module',
});
const visitor = {
BlockStatement(path) {
// path.node.body 是直接访问当前节点的 body 属性的值,返回一个数组(通常是一组语句节点)。
// path.get('body') 是通过路径对象的方法获取当前节点的 body 属性的子路径,你可以在这个子路径上进行更多的操作。
let body = path.node.body;
console.log(body);
body.pop()
},
};
traverse(ast, visitor);
// 将修改后的AST重新生成为代码
const modifiedCode = generator(ast).code;
console.log(modifiedCode);

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var a = "123", b = 123;

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function test(){
var a = 123;
c = a + b;
crack();
}

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