feat: 实现es6的class转换 基本版

learnWebpack/ast-demo/4.js

@@ -0,0 +1,92 @@
+const core = require('@babel/core');
+// const { types, template } = core;
+const types = require('babel-types')
+const template = require('@babel/template')
+let code = `
+function a(x, y) {
+    console.log(x, y);
+    return x + y
+}
+`
+
+function parseCodeStringToStatement(str) {
+    let arr = str.split('\n').filter(i => i !== '');
+    // console.log(arr)
+    return arr.map(s => template.statement(s)())
+}
+
+
+const error = 'error'
+
+let customeCode = `
+console.log(${error});
+`
+
+let parseResult = parseCodeStringToStatement(customeCode);
+let plugin = {
+    visitor: {
+        FunctionDeclaration(nodePath) {
+            let {node} = nodePath;
+            let {id} = node.id;
+            let blockStatement = node.body;
+            if (blockStatement.body && types.isTryStatement(blockStatement.body[0])) return;
+
+            // let catchStatement = template.statement(`
+            //     console.log(error, 1);
+            // `)();
+
+            //  // [catchStatement, template.statement('console.log(\'hello world\')')()]
+            let catchClause = types.catchClause(types.identifier(error), types.blockStatement(parseResult));
+
+            let tryStatement = types.tryStatement(blockStatement, catchClause);
+            let func = types.functionExpression(id, node.params, types.blockStatement([tryStatement]), node.generator, node.async);
+            nodePath.replaceWith(func)
+        }
+    }
+}
+
+
+// let res = core.transform(code, {
+//     plugins: [plugin]
+// });
+
+// console.log(res.code)
+
+function parse(code, errorName, errorBody) {
+    const parseResult = parseCodeStringToStatement(errorBody)
+    let plugin = {
+        visitor: {
+            FunctionDeclaration(nodePath) {
+                let {node} = nodePath;
+                let {id} = node.id;
+                let blockStatement = node.body;
+                if (blockStatement.body && types.isTryStatement(blockStatement.body[0])) return;
+
+                // let catchStatement = template.statement(`
+                //     console.log(error, 1);
+                // `)();
+
+                //  // [catchStatement, template.statement('console.log(\'hello world\')')()]
+                let catchClause = types.catchClause(types.identifier(errorName), types.blockStatement(parseResult));
+
+                let tryStatement = types.tryStatement(blockStatement, catchClause);
+                let func = types.functionExpression(id, node.params, types.blockStatement([tryStatement]), node.generator, node.async);
+                nodePath.replaceWith(func)
+            }
+        }
+    }
+    return core.transform(code, {
+        plugins: [plugin]
+    }).code;
+}
+
+// console.log(parse(`
+// function add(x, y) {
+//     console.log(x, y);
+//     return x + y;
+// }
+// `, 'error', `console.log(error)`))
+
+let rt = JSON.stringify(core.parse(`let a = 1`).program, null ,2)
+console.log(rt);
+module.exports = parse;

learnWebpack/ast-demo/README.md

@@ -234,8 +234,14 @@ const myClassTransformPlugin = {
 ```
 
 > babel-types 不用安装，core里面其实也有
+还有template
 
 ```js
 // const types = require('babel-types');
-const {types} = core
-```
+// const template = require('@babel/template');
+const {types, template} = core
+```
+
+以上实现代码查看 (./4.js)['./4.js']
+
+## 实现tree-shaking