12.AST操作之如何插入节点-insertAfter-insertBefore

AST抽象语法树/12.AST操作之如何插入节点-insertAfter-insertBefore/README.md

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+# 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
+
+```javascript
+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);
+```

AST抽象语法树/12.AST操作之如何插入节点-insertAfter-insertBefore/decode_obfuscator.js

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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;
+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);

AST抽象语法树/12.AST操作之如何插入节点-insertAfter-insertBefore/encode.js

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+var a = 123;