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36 lines
1007 B
Markdown
36 lines
1007 B
Markdown
# AST操作之如何插入节点
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需求：var a = 123;后面增加一个兄弟节点b = 111
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```javascript
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const fs = require('fs');
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const {parse} = require("@babel/parser");
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const traverse = require("@babel/traverse").default;
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const generator = require("@babel/generator").default;
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const t = require('@babel/types');
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let encode_file = "./encode.js";
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let js_code = fs.readFileSync(encode_file, {encoding: "utf-8"});
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let ast = parse(js_code, {
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sourceType: 'module',
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});
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const visitor = {
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VariableDeclarator(path) {
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let {id} = path.node;
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// 这里一定要判断准确，否则会无限循环
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if(id.name == 'a'){
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let new_id = t.Identifier("b");
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let new_init = t.NumericLiteral(111);
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let new_node = t.VariableDeclarator(new_id, new_init);
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path.insertAfter(new_node)
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}
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},
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};
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traverse(ast, visitor);
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// 将修改后的AST重新生成为代码
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const modifiedCode = generator(ast).code;
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console.log(modifiedCode);
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``` |