@expo/metro-config
Version:
A Metro config for running React Native projects with the Metro bundler
67 lines • 2.91 kB
JavaScript
;
var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
var desc = Object.getOwnPropertyDescriptor(m, k);
if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
desc = { enumerable: true, get: function() { return m[k]; } };
}
Object.defineProperty(o, k2, desc);
}) : (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
o[k2] = m[k];
}));
var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
Object.defineProperty(o, "default", { enumerable: true, value: v });
}) : function(o, v) {
o["default"] = v;
});
var __importStar = (this && this.__importStar) || function (mod) {
if (mod && mod.__esModule) return mod;
var result = {};
if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
__setModuleDefault(result, mod);
return result;
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.transformSync = void 0;
/**
* Copyright (c) 650 Industries (Expo). All rights reserved.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
const babel = __importStar(require("./babel-core"));
// TS detection conditions copied from @react-native/babel-preset
function isTypeScriptSource(fileName) {
return fileName?.endsWith('.ts');
}
function isTSXSource(fileName) {
return fileName?.endsWith('.tsx');
}
function transformSync(src, babelConfig, { hermesParser }) {
const isTypeScript = isTypeScriptSource(babelConfig.filename) || isTSXSource(babelConfig.filename);
if (isTypeScript) {
return parseWithBabel(src, babelConfig);
}
if (!isTypeScript &&
// The Hermes parser doesn't support comments or babel proposals such as export default from, meaning it has lower compatibility with larger parts
// of the ecosystem.
// However, React Native ships with flow syntax that isn't supported in Babel so we need to use Hermes for those files.
// We can try to quickly detect if the file uses flow syntax by checking for the @flow pragma which is present in every React Native file.
(hermesParser || src.includes(' @flow'))) {
return parseWithHermes(src, babelConfig);
}
return parseWithBabel(src, babelConfig);
}
exports.transformSync = transformSync;
function parseWithHermes(src, babelConfig) {
const sourceAst = require('hermes-parser').parse(src, {
babel: true,
sourceType: babelConfig.sourceType,
});
return babel.transformFromAstSync(sourceAst, src, babelConfig);
}
function parseWithBabel(src, babelConfig) {
return babel.transformSync(src, babelConfig);
}
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