add escodegen & estraverse

jerryOnlyZRJ · Feb 12, 2019 · a24ee3e · a24ee3e
1 parent 37cc8b7
commit a24ee3e
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Showing 8 changed files with 266 additions and 31 deletions.
diff --git a/dist/common/utils.js b/dist/common/utils.js
@@ -7,7 +7,7 @@
 /*! no static exports found */
 /***/ (function(module, exports, __webpack_require__) {
 
-eval("{};var s = __webpack_require__(/*! ./module.js */ \"./src/module.js\");\n\nconsole.log(s.s);\n\n//# sourceURL=webpack:///./src/index.js?");
+eval("{}\n;\n\nvar s = __webpack_require__(/*! ./module.js */ \"./src/module.js\");\n\nconsole.log(s.s);\n\n//# sourceURL=webpack:///./src/index.js?");
 
 /***/ }),
 
@@ -18,7 +18,7 @@ eval("{};var s = __webpack_require__(/*! ./module.js */ \"./src/module.js\");\n\
 /*! no static exports found */
 /***/ (function(module, exports) {
 
-eval("{};var s = 123;\nconsole.log(s);\nmodule.exports = {\n  s: s\n};\n\n//# sourceURL=webpack:///./src/module.js?");
+eval("{}\n;\nvar s = 123;\nconsole.log(s);\nmodule.exports = {\n  s: s\n};\n\n//# sourceURL=webpack:///./src/module.js?");
 
 /***/ })
 

diff --git a/loaders/babel/ast.js b/loaders/babel/ast.js
@@ -0,0 +1,117 @@
+module.exports = {
+    "type": "Program",
+    "start": 0,
+    "end": 57,
+    "body": [{
+        "type": "VariableDeclaration",
+        "start": 0,
+        "end": 12,
+        "declarations": [{
+            "type": "VariableDeclarator",
+            "start": 4,
+            "end": 11,
+            "id": {
+                "type": "Identifier",
+                "start": 4,
+                "end": 5,
+                "name": "s"
+            },
+            "init": {
+                "type": "Literal",
+                "start": 8,
+                "end": 11,
+                "value": 123,
+                "raw": "123"
+            }
+        }],
+        "kind": "var"
+    }, {
+        "type": "ExpressionStatement",
+        "start": 13,
+        "end": 28,
+        "expression": {
+            "type": "CallExpression",
+            "start": 13,
+            "end": 27,
+            "callee": {
+                "type": "MemberExpression",
+                "start": 13,
+                "end": 24,
+                "object": {
+                    "type": "Identifier",
+                    "start": 13,
+                    "end": 20,
+                    "name": "console"
+                },
+                "property": {
+                    "type": "Identifier",
+                    "start": 21,
+                    "end": 24,
+                    "name": "log"
+                },
+                "computed": false
+            },
+            "arguments": [{
+                "type": "Identifier",
+                "start": 25,
+                "end": 26,
+                "name": "s"
+            }]
+        }
+    }, {
+        "type": "ExpressionStatement",
+        "start": 29,
+        "end": 57,
+        "expression": {
+            "type": "AssignmentExpression",
+            "start": 29,
+            "end": 56,
+            "operator": "=",
+            "left": {
+                "type": "MemberExpression",
+                "start": 29,
+                "end": 43,
+                "object": {
+                    "type": "Identifier",
+                    "start": 29,
+                    "end": 35,
+                    "name": "module"
+                },
+                "property": {
+                    "type": "Identifier",
+                    "start": 36,
+                    "end": 43,
+                    "name": "exports"
+                },
+                "computed": false
+            },
+            "right": {
+                "type": "ObjectExpression",
+                "start": 46,
+                "end": 56,
+                "properties": [{
+                    "type": "Property",
+                    "start": 50,
+                    "end": 54,
+                    "method": false,
+                    "shorthand": false,
+                    "computed": false,
+                    "key": {
+                        "type": "Identifier",
+                        "start": 50,
+                        "end": 51,
+                        "name": "s"
+                    },
+                    "value": {
+                        "type": "Identifier",
+                        "start": 53,
+                        "end": 54,
+                        "name": "s"
+                    },
+                    "kind": "init"
+                }]
+            }
+        }
+    }],
+    "sourceType": "script"
+}
diff --git a/loaders/babel/index.js b/loaders/babel/index.js
@@ -0,0 +1,24 @@
+// code -> AST
+const acorn = require('acorn')
+// 遍历AST 
+const estraverse = require('estraverse')
+// AST -> code
+const escodegen = require('escodegen')
+
+module.exports = function (content) {
+    // AST解析过程模拟
+    const AST_Object = acorn.parse(content)
+    // 结果见 ./ast.js
+    console.log("AST静态语法树：", AST_Object)
+    // 遍历AST
+    estraverse.traverse(AST_Object, {
+        enter: function (node, parent) {
+            if (node.type == 'VariableDeclaration') {
+                console.log("遍历AST拿到const：", node.kind)
+                node.kind = 'var'
+            }
+        }
+    });
+    // AST -> code
+    console.log('AST替换之后生成的代码：', escodegen.generate(AST_Object))
+}
diff --git a/loaders/index.js b/loaders/index.js
@@ -1,18 +1,18 @@
 // loader是链式调用的，上一个loader会将处理结果传给下一个loader
-//content是loader匹配到的单个文件内容 【String】
+// content是loader匹配到的单个文件内容 【String】
 // 如果use是个loaders数组，则从后往前执行，pitch会被挂载在数组末端，最先执行
 
-const loaderUtils = require("loader-utils");
-const acorn = require("acorn")
+const loaderUtils = require('loader-utils');
+// 模拟babel功能
+const babel = require('./babel')
 
 /**
  * loader Function
  * @param {String} content 文件内容
  */
 module.exports = async function (content) {
-    // AST解析过程模拟
-    const AST_Object = acorn.parse(content)
-    console.log("AST静态语法树", AST_Object)
+    babel(content)
+    // webpack-loader实战
     // 获取用户配置的options
     const options = loaderUtils.getOptions(this);
     /**