| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | */ |
| 7 | |
| 8 | import type * as BabelCore from '@babel/core'; |
| 9 | import {NodePath} from '@babel/core'; |
| 10 | import * as t from '@babel/types'; |
| 11 | |
| 12 | export default function AnnotateReactCodeBabelPlugin( |
| 13 | _babel: typeof BabelCore, |
| 14 | ): BabelCore.PluginObj { |
| 15 | return { |
| 16 | name: 'annotate-react-code', |
| 17 | visitor: { |
| 18 | Program(prog): void { |
| 19 | annotate(prog); |
| 20 | }, |
| 21 | }, |
| 22 | }; |
| 23 | } |
| 24 | |
| 25 | function annotate(program: NodePath<t.Program>): void { |
| 26 | function traverseFn(fn: BabelFn): void { |
| 27 | if (!shouldVisit(fn)) { |
| 28 | return; |
| 29 | } |
| 30 | |
| 31 | fn.skip(); |
| 32 | |
| 33 | const body = fn.node.body; |
| 34 | if (t.isBlockStatement(body)) { |
| 35 | body.body.unshift(buildTypeOfReactForget()); |
| 36 | } |
| 37 | } |
| 38 | |
| 39 | program.traverse({ |
| 40 | FunctionDeclaration: traverseFn, |
| 41 | FunctionExpression: traverseFn, |
| 42 | ArrowFunctionExpression: traverseFn, |
| 43 | }); |
| 44 | } |
| 45 | |
| 46 | function shouldVisit(fn: BabelFn): boolean { |
| 47 | return ( |
| 48 | // Component declarations are known components |
| 49 | (fn.isFunctionDeclaration() && isComponentDeclaration(fn.node)) || |
| 50 | // Otherwise check if this is a component or hook-like function |
| 51 | isComponentOrHookLike(fn) |
| 52 | ); |
| 53 | } |
| 54 | |
| 55 | function buildTypeOfReactForget(): t.Statement { |
| 56 | // typeof globalThis[Symbol.for("react_forget")] |
| 57 | return t.expressionStatement( |
| 58 | t.unaryExpression( |
| 59 | 'typeof', |
| 60 | t.memberExpression( |
| 61 | t.identifier('globalThis'), |
| 62 | t.callExpression( |
| 63 | t.memberExpression( |
| 64 | t.identifier('Symbol'), |
| 65 | t.identifier('for'), |
| 66 | false, |
| 67 | false, |
| 68 | ), |
| 69 | [t.stringLiteral('react_forget')], |
| 70 | ), |
| 71 | true, |
| 72 | false, |
| 73 | ), |
| 74 | true, |
| 75 | ), |
| 76 | ); |
| 77 | } |
| 78 | |
| 79 | /** |
| 80 | * COPIED FROM babel-plugin-react-compiler/src/Entrypoint/BabelUtils.ts |
| 81 | */ |
| 82 | type ComponentDeclaration = t.FunctionDeclaration & { |
| 83 | __componentDeclaration: boolean; |
| 84 | }; |
| 85 | |
| 86 | type BabelFn = |
| 87 | | NodePath<t.FunctionDeclaration> |
| 88 | | NodePath<t.FunctionExpression> |
| 89 | | NodePath<t.ArrowFunctionExpression>; |
| 90 | |
| 91 | export function isComponentDeclaration( |
| 92 | node: t.FunctionDeclaration, |
| 93 | ): node is ComponentDeclaration { |
| 94 | return Object.prototype.hasOwnProperty.call(node, '__componentDeclaration'); |
| 95 | } |
| 96 | |
| 97 | /* |
| 98 | * Adapted from the ESLint rule at |
| 99 | * https://github.com/facebook/react/blob/main/packages/eslint-plugin-react-hooks/src/RulesOfHooks.js#L90-L103 |
| 100 | */ |
| 101 | function isComponentOrHookLike( |
| 102 | node: NodePath< |
| 103 | t.FunctionDeclaration | t.ArrowFunctionExpression | t.FunctionExpression |
| 104 | >, |
| 105 | ): boolean { |
| 106 | const functionName = getFunctionName(node); |
| 107 | // Check if the name is component or hook like: |
| 108 | if (functionName !== null && isComponentName(functionName)) { |
| 109 | return ( |
| 110 | // As an added check we also look for hook invocations or JSX |
| 111 | callsHooksOrCreatesJsx(node) && |
| 112 | /* |
| 113 | * and avoid helper functions that take more than one argument |
| 114 | * helpers are _usually_ named with lowercase, but some code may |
| 115 | * violate this rule |
| 116 | */ |
| 117 | node.get('params').length <= 1 |
| 118 | ); |
| 119 | } else if (functionName !== null && isHook(functionName)) { |
| 120 | // Hooks have hook invocations or JSX, but can take any # of arguments |
| 121 | return callsHooksOrCreatesJsx(node); |
| 122 | } |
| 123 | |
| 124 | /* |
| 125 | * Otherwise for function or arrow function expressions, check if they |
| 126 | * appear as the argument to React.forwardRef() or React.memo(): |
| 127 | */ |
| 128 | if (node.isFunctionExpression() || node.isArrowFunctionExpression()) { |
| 129 | if (isForwardRefCallback(node) || isMemoCallback(node)) { |
| 130 | // As an added check we also look for hook invocations or JSX |
| 131 | return callsHooksOrCreatesJsx(node); |
| 132 | } else { |
| 133 | return false; |
| 134 | } |
| 135 | } |
| 136 | return false; |
| 137 | } |
| 138 | |
| 139 | function isHookName(s: string): boolean { |
| 140 | return /^use[A-Z0-9]/.test(s); |
| 141 | } |
| 142 | |
| 143 | /* |
| 144 | * We consider hooks to be a hook name identifier or a member expression |
| 145 | * containing a hook name. |
| 146 | */ |
| 147 | |
| 148 | function isHook(path: NodePath<t.Expression | t.PrivateName>): boolean { |
| 149 | if (path.isIdentifier()) { |
| 150 | return isHookName(path.node.name); |
| 151 | } else if ( |
| 152 | path.isMemberExpression() && |
| 153 | !path.node.computed && |
| 154 | isHook(path.get('property')) |
| 155 | ) { |
| 156 | const obj = path.get('object').node; |
| 157 | const isPascalCaseNameSpace = /^[A-Z].*/; |
| 158 | return obj.type === 'Identifier' && isPascalCaseNameSpace.test(obj.name); |
| 159 | } else { |
| 160 | return false; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | /* |
| 165 | * Checks if the node is a React component name. React component names must |
| 166 | * always start with an uppercase letter. |
| 167 | */ |
| 168 | |
| 169 | function isComponentName(path: NodePath<t.Expression>): boolean { |
| 170 | return path.isIdentifier() && /^[A-Z]/.test(path.node.name); |
| 171 | } |
| 172 | /* |
| 173 | * Checks if the node is a callback argument of forwardRef. This render function |
| 174 | * should follow the rules of hooks. |
| 175 | */ |
| 176 | |
| 177 | function isForwardRefCallback(path: NodePath<t.Expression>): boolean { |
| 178 | return !!( |
| 179 | path.parentPath.isCallExpression() && |
| 180 | path.parentPath.get('callee').isExpression() && |
| 181 | isReactAPI(path.parentPath.get('callee'), 'forwardRef') |
| 182 | ); |
| 183 | } |
| 184 | |
| 185 | /* |
| 186 | * Checks if the node is a callback argument of React.memo. This anonymous |
| 187 | * functional component should follow the rules of hooks. |
| 188 | */ |
| 189 | |
| 190 | function isMemoCallback(path: NodePath<t.Expression>): boolean { |
| 191 | return ( |
| 192 | path.parentPath.isCallExpression() && |
| 193 | path.parentPath.get('callee').isExpression() && |
| 194 | isReactAPI(path.parentPath.get('callee'), 'memo') |
| 195 | ); |
| 196 | } |
| 197 | |
| 198 | function isReactAPI( |
| 199 | path: NodePath<t.Expression | t.PrivateName | t.V8IntrinsicIdentifier>, |
| 200 | functionName: string, |
| 201 | ): boolean { |
| 202 | const node = path.node; |
| 203 | return ( |
| 204 | (node.type === 'Identifier' && node.name === functionName) || |
| 205 | (node.type === 'MemberExpression' && |
| 206 | node.object.type === 'Identifier' && |
| 207 | node.object.name === 'React' && |
| 208 | node.property.type === 'Identifier' && |
| 209 | node.property.name === functionName) |
| 210 | ); |
| 211 | } |
| 212 | |
| 213 | function callsHooksOrCreatesJsx(node: NodePath<t.Node>): boolean { |
| 214 | let invokesHooks = false; |
| 215 | let createsJsx = false; |
| 216 | node.traverse({ |
| 217 | JSX() { |
| 218 | createsJsx = true; |
| 219 | }, |
| 220 | CallExpression(call) { |
| 221 | const callee = call.get('callee'); |
| 222 | if (callee.isExpression() && isHook(callee)) { |
| 223 | invokesHooks = true; |
| 224 | } |
| 225 | }, |
| 226 | }); |
| 227 | |
| 228 | return invokesHooks || createsJsx; |
| 229 | } |
| 230 | |
| 231 | /* |
| 232 | * Gets the static name of a function AST node. For function declarations it is |
| 233 | * easy. For anonymous function expressions it is much harder. If you search for |
| 234 | * `IsAnonymousFunctionDefinition()` in the ECMAScript spec you'll find places |
| 235 | * where JS gives anonymous function expressions names. We roughly detect the |
| 236 | * same AST nodes with some exceptions to better fit our use case. |
| 237 | */ |
| 238 | |
| 239 | function getFunctionName( |
| 240 | path: NodePath< |
| 241 | t.FunctionDeclaration | t.ArrowFunctionExpression | t.FunctionExpression |
| 242 | >, |
| 243 | ): NodePath<t.Expression> | null { |
| 244 | if (path.isFunctionDeclaration()) { |
| 245 | const id = path.get('id'); |
| 246 | if (id.isIdentifier()) { |
| 247 | return id; |
| 248 | } |
| 249 | return null; |
| 250 | } |
| 251 | let id: NodePath<t.LVal | t.Expression | t.PrivateName> | null = null; |
| 252 | const parent = path.parentPath; |
| 253 | if (parent.isVariableDeclarator() && parent.get('init').node === path.node) { |
| 254 | // const useHook = () => {}; |
| 255 | id = parent.get('id'); |
| 256 | } else if ( |
| 257 | parent.isAssignmentExpression() && |
| 258 | parent.get('right').node === path.node && |
| 259 | parent.get('operator') === '=' |
| 260 | ) { |
| 261 | // useHook = () => {}; |
| 262 | id = parent.get('left'); |
| 263 | } else if ( |
| 264 | parent.isProperty() && |
| 265 | parent.get('value').node === path.node && |
| 266 | !parent.get('computed') && |
| 267 | parent.get('key').isLVal() |
| 268 | ) { |
| 269 | /* |
| 270 | * {useHook: () => {}} |
| 271 | * {useHook() {}} |
| 272 | */ |
| 273 | id = parent.get('key'); |
| 274 | } else if ( |
| 275 | parent.isAssignmentPattern() && |
| 276 | parent.get('right').node === path.node && |
| 277 | !parent.get('computed') |
| 278 | ) { |
| 279 | /* |
| 280 | * const {useHook = () => {}} = {}; |
| 281 | * ({useHook = () => {}} = {}); |
| 282 | * |
| 283 | * Kinda clowny, but we'd said we'd follow spec convention for |
| 284 | * `IsAnonymousFunctionDefinition()` usage. |
| 285 | */ |
| 286 | id = parent.get('left'); |
| 287 | } |
| 288 | if (id !== null && (id.isIdentifier() || id.isMemberExpression())) { |
| 289 | return id; |
| 290 | } else { |
| 291 | return null; |
| 292 | } |
| 293 | } |