index.js

const path = require("path");
const { existsSync } = require("fs");

const { ANDROID_APP_PATH } = require("./androidProjectHelpers");
const {
    getPackageJson,
    isAndroid,
    isIos,
} = require("./projectHelpers");

Object.assign(exports, require("./plugins"));
Object.assign(exports, require("./host/resolver"));

exports.getAotEntryModule = function (appDirectory) {
	verifyEntryModuleDirectory(appDirectory);
    
    const entry = getPackageJsonEntry(appDirectory);
    const aotEntry = `${entry}.aot.ts`;

    const aotEntryPath = path.resolve(appDirectory, aotEntry);
    if (!existsSync(aotEntryPath)) {
        throw new Error(`For ahead-of-time compilation you need to have an entry module ` +
        `at ${aotEntryPath} that bootstraps the app with a static platform instead of dynamic one!`)
    }

    return aotEntry;
}

exports.getEntryModule = function (appDirectory) {
	verifyEntryModuleDirectory(appDirectory);

    const entry = getPackageJsonEntry(appDirectory);

    const tsEntryPath = path.resolve(appDirectory, `${entry}.ts`);
    const jsEntryPath = path.resolve(appDirectory, `${entry}.js`);
    if (!existsSync(tsEntryPath) && !existsSync(jsEntryPath)) {
        throw new Error(`The entry module ${entry} specified in ` +
        `${appDirectory}/package.json doesn't exist!`)
    }

    return entry;
};

exports.getAppPath = (platform, projectDir) => {
    if (isIos(platform)) {
        const appName = path.basename(projectDir);
        const sanitizedName = sanitize(appName);

        return `platforms/ios/${sanitizedName}/app`;
    } else if (isAndroid(platform)) {
        return ANDROID_APP_PATH;
    } else {
        throw new Error(`Invalid platform: ${platform}`);
    }
};

const sanitize = name => name
    .split("")
    .filter(char => /[a-zA-Z0-9]/.test(char))
    .join("");

function getPackageJsonEntry(appDirectory) {
    const packageJsonSource = getPackageJson(appDirectory);
    const entry = packageJsonSource.main;

    if (!entry) {
        throw new Error(`${appDirectory}/package.json must contain a 'main' attribute!`);
    }

    return entry.replace(/\.js$/i, "");
}

function verifyEntryModuleDirectory(appDirectory) {
    if (!appDirectory) {
		throw new Error("Path to app directory is not specified. Unable to find entry module.");
	}

	if (!existsSync(appDirectory)) {
		throw new Error(`The specified path to app directory ${appDirectory} does not exist. Unable to find entry module.`);
	}
}