Use Preconstruct

.gitignore

@@ -1,2 +1,2 @@
 node_modules
-lib
+dist

lib/index.js

@@ -0,0 +1,85 @@
+'use strict'
+
+Object.defineProperty(exports, '__esModule', {
+  value: true,
+})
+exports.default = void 0
+const PURE_ANNOTATION = '#__PURE__'
+const isPureAnnotated = node => {
+  const leadingComments = node.leadingComments
+  if (!leadingComments) {
+    return false
+  }
+  return leadingComments.some(comment => /[@#]__PURE__/.test(comment.value))
+}
+const annotateAsPure = path => {
+  if (isPureAnnotated(path.node)) {
+    return
+  }
+  path.addComment('leading', PURE_ANNOTATION)
+}
+const hasCallableParent = ({ parentPath }) =>
+  parentPath.isCallExpression() || parentPath.isNewExpression()
+const isUsedAsCallee = path => {
+  if (!hasCallableParent(path)) {
+    return false
+  }
+  return path.parentPath.get('callee') === path
+}
+const isInCallee = path => {
+  do {
+    path = path.parentPath
+    if (isUsedAsCallee(path)) {
+      return true
+    }
+  } while (!path.isStatement() && !path.isFunction())
+  return false
+}
+const isExecutedDuringInitialization = path => {
+  let functionParent = path.getFunctionParent()
+  while (functionParent) {
+    if (!isUsedAsCallee(functionParent)) {
+      return false
+    }
+    functionParent = functionParent.getFunctionParent()
+  }
+  return true
+}
+const isInAssignmentContext = path => {
+  const statement = path.getStatementParent()
+  let parentPath
+  do {
+    var _ref = parentPath || path
+    parentPath = _ref.parentPath
+    if (
+      parentPath.isVariableDeclaration() ||
+      parentPath.isAssignmentExpression() ||
+      parentPath.isClass()
+    ) {
+      return true
+    }
+  } while (parentPath !== statement)
+  return false
+}
+const callableExpressionVisitor = path => {
+  if (isUsedAsCallee(path) || isInCallee(path)) {
+    return
+  }
+  if (!isExecutedDuringInitialization(path)) {
+    return
+  }
+  if (
+    !isInAssignmentContext(path) &&
+    !path.getStatementParent().isExportDefaultDeclaration()
+  ) {
+    return
+  }
+  annotateAsPure(path)
+}
+var _default = () => ({
+  name: 'annotate-pure-calls',
+  visitor: {
+    'CallExpression|NewExpression': callableExpressionVisitor,
+  },
+})
+exports.default = _default

package.json

@@ -4,9 +4,22 @@
   "description": "Babel plugin for annotating automatically pure function calls.",
   "author": "Mateusz Burzyński <[email protected]> (https://github.com/Andarist)",
   "license": "MIT",
-  "main": "lib/index.js",
+  "main": "dist/babel-plugin-annotate-pure-calls.cjs.js",
+  "module": "dist/babel-plugin-annotate-pure-calls.esm.js",
+  "exports": {
+    ".": {
+      "types": {
+        "import": "./dist/babel-plugin-annotate-pure-calls.cjs.mjs",
+        "default": "./dist/babel-plugin-annotate-pure-calls.cjs.js"
+      },
+      "module": "./dist/babel-plugin-annotate-pure-calls.esm.js",
+      "import": "./dist/babel-plugin-annotate-pure-calls.cjs.mjs",
+      "default": "./dist/babel-plugin-annotate-pure-calls.cjs.js"
+    },
+    "./package.json": "./package.json"
+  },
   "files": [
-    "lib"
+    "dist"
   ],
   "repository": {
     "type": "git",
@@ -23,7 +36,6 @@
     "url": "https://github.com/Andarist/babel-plugin-annotate-pure-calls/issues"
   },
   "homepage": "https://github.com/Andarist/babel-plugin-annotate-pure-calls#readme",
-  "dependencies": {},
   "peerDependencies": {
     "@babel/core": "^7.0.0"
   },
@@ -32,14 +44,15 @@
     "@babel/core": "^7.1.0",
     "@babel/plugin-transform-modules-commonjs": "^7.1.0",
     "@babel/preset-env": "^7.1.0",
+    "@preconstruct/cli": "^2.8.10",
     "babel-plugin-tester": "^5.4.0",
     "husky": "^0.14.3",
     "jest": "^23.1.0",
     "lint-staged": "^7.1.3",
     "prettier": "^1.13.5"
   },
   "scripts": {
-    "build": "babel src --out-dir lib",
+    "build": "preconstruct build",
     "pretest": "npm run build",
     "test": "jest",
     "precommit": "lint-staged",
@@ -56,5 +69,13 @@
     "semi": false,
     "trailingComma": "all",
     "proseWrap": "always"
+  },
+  "preconstruct": {
+    "exports": {
+      "importConditionDefaultExport": "default"
+    },
+    "___experimentalFlags_WILL_CHANGE_IN_PATCH": {
+      "importsConditions": true
+    }
   }
 }