/** * Copyright (c) Meta Platforms, Inc. and affiliates. * * This source code is licensed under the MIT license found in the * LICENSE file in the root directory of this source tree. * * @flow strict-local * @format */ import type { File as BabelNodeFile, FunctionExpression, Identifier, Program, } from '@babel/types'; import template from '@babel/template'; import * as t from '@babel/types'; // Check first the `global` variable as the global object. This way serializers // can create a local variable called global to fake it as a global object // without having to pollute the window object on web. const IIFE_PARAM = template.expression( "typeof globalThis !== 'undefined' ? globalThis : typeof global !== 'undefined' ? global : typeof window !== 'undefined' ? window : this", ); function wrapModule( fileAst: BabelNodeFile, importDefaultName: string, importAllName: string, dependencyMapName: string, globalPrefix: string, { unstable_useStaticHermesModuleFactory = false, }: Readonly<{unstable_useStaticHermesModuleFactory?: boolean}> = {}, ): { ast: BabelNodeFile, requireName: string, } { const params = buildParameters( importDefaultName, importAllName, dependencyMapName, ); const factory = functionFromProgram(fileAst.program, params); const def = t.callExpression(t.identifier(`${globalPrefix}__d`), [ unstable_useStaticHermesModuleFactory ? t.callExpression( t.memberExpression( t.identifier('$SHBuiltin'), t.identifier('moduleFactory'), ), [t.identifier('_$$_METRO_MODULE_ID'), factory], ) : factory, ]); const ast = t.file(t.program([t.expressionStatement(def)])); // `require` is never scoped/renamed: the local `require` function parameter is // used instead of the global one when Metro serializes to the IIFE module // factory. return {ast, requireName: 'require'}; } function wrapPolyfill(fileAst: BabelNodeFile): BabelNodeFile { const factory = functionFromProgram(fileAst.program, ['global']); const iife = t.callExpression(factory, [IIFE_PARAM()]); return t.file(t.program([t.expressionStatement(iife)])); } function jsonToCommonJS(source: string): string { return `module.exports = ${source};`; } function wrapJson( source: string, globalPrefix: string, unstable_useStaticHermesModuleFactory?: boolean = false, ): string { // The factory-parameter defaults (`_importDefaultUnused` etc.) are safe // for JSON, whose body only references `module` / `module.exports`. return wrapModuleString(jsonToCommonJS(source), globalPrefix, { unstable_useStaticHermesModuleFactory, }); } /** * Wraps an arbitrary JS `body` source string as a `__d(function(...) { })` * module definition, with pure string manipulation. * * This is the lower-level primitive that `wrapJson` builds on - it is also * exposed for callers that need to synthesize `__d`-wrapped modules from * strings cheaply (e.g. codegen of synthetic segment/metadata modules). * * Factory parameter names default to the `_*Unused` names `wrapJson` emits. * Callers whose body references one of these slots by name (typically the * dependency-map parameter) must pass the corresponding option so the emitted * factory signature exposes that name. Callers are responsible for ensuring * that the body does not unintentionally shadow or redeclare parameters. */ function wrapModuleString( body: string, globalPrefix: string, { importDefaultName = '_importDefaultUnused', importAllName = '_importAllUnused', dependencyMapName = '_dependencyMapUnused', unstable_useStaticHermesModuleFactory = false, }: Readonly<{ importDefaultName?: string, importAllName?: string, dependencyMapName?: string, unstable_useStaticHermesModuleFactory?: boolean, }> = {}, ): string { const moduleFactoryParameters = buildParameters( importDefaultName, importAllName, dependencyMapName, ); const factory = [ `function(${moduleFactoryParameters.join(', ')}) {`, ` ${body}`, '}', ].join('\n'); return ( `${globalPrefix}__d(` + (unstable_useStaticHermesModuleFactory ? '$SHBuiltin.moduleFactory(_$$_METRO_MODULE_ID, ' + factory + ')' : factory) + ');' ); } function functionFromProgram( program: Program, parameters: ReadonlyArray, ): FunctionExpression { return t.functionExpression( undefined, parameters.map(makeIdentifier), t.blockStatement(program.body, program.directives), ); } function makeIdentifier(name: string): Identifier { return t.identifier(name); } function buildParameters( importDefaultName: string, importAllName: string, dependencyMapName: string, ): ReadonlyArray { return [ 'global', 'require', importDefaultName, importAllName, 'module', 'exports', dependencyMapName, ]; } export {wrapJson, jsonToCommonJS, wrapModule, wrapModuleString, wrapPolyfill};