public static determineIonicMajorVersion()

in src/utils/cordovaProjectHelper.ts [275:390]
93 lines of code
28 McCabe index (conditional complexity)

    public static determineIonicMajorVersion(projectRoot: string): number | undefined {
        // Ionic 1 check
        // First look for "ionic.project" at the project root
        if (fs.existsSync(path.join(projectRoot, CordovaProjectHelper.IONIC_PROJECT_FILE))) {
            return 1;

        // If not found, fall back to looking for "www/lib/ionic" folder. This isn't a 100% guarantee though: an Ionic project doesn't necessarily have an "ionic.project" and could have the Ionic lib
        // files in a non-default location
        } else if (fs.existsSync(path.join(projectRoot, CordovaProjectHelper.IONIC_LIB_DEFAULT_PATH))) {
            return 1;
        }

        const packageJsonPath = path.join(projectRoot, "package.json");
        if (!fs.existsSync(packageJsonPath)) {
            return;
        }
        const packageJson = JSON.parse(fs.readFileSync(packageJsonPath, "utf-8"));
        const dependencies = packageJson.dependencies || {};
        const devDependencies = packageJson.devDependencies || {};

        // Ionic 2 & 3 check
        const highestNotSupportedIonic2BetaVersion = "2.0.0-beta.9";
        const highestNotSupportedIonic3BetaVersion = "3.0.0-beta.3";
        if ((dependencies["ionic-angular"]) && (devDependencies["@ionic/app-scripts"] || dependencies["@ionic/app-scripts"])) {
            const ionicVersion = dependencies["ionic-angular"];

            // If it's a valid version let's check it's greater than highest not supported Ionic major version beta
            if (semver.valid(ionicVersion)) {
                if (CordovaProjectHelper.versionSatisfiesInterval(
                    ionicVersion,
                    highestNotSupportedIonic2BetaVersion,
                    "3.0.0")
                ) {
                    return 2;
                }
                if (semver.gt(ionicVersion, highestNotSupportedIonic3BetaVersion)) {
                    return 3;
                }
            }

            // If it's a valid range we check that the entire range is greater than highest not supported Ionic major version beta
            if (semver.validRange(ionicVersion)) {
                if (CordovaProjectHelper.versionRangeSatisfiesInterval(
                    ionicVersion,
                    highestNotSupportedIonic2BetaVersion,
                    "3.0.0")
                ) {
                    return 2;
                }
                if (semver.ltr(highestNotSupportedIonic3BetaVersion, ionicVersion)) {
                    return 3;
                }
            }

            // Assuming for now that latest version is 3
            if (ionicVersion === "latest" || ionicVersion === "nightly") {
                return 3;
            }
        }

        // Ionic 4, 5, 6 check
        const highestNotSupportedIonic4BetaVersion = "4.0.0-beta.19";
        const highestNotSupportedIonic5BetaVersion = "5.0.0-beta.6";
        const highestNotSupportedIonic6BetaVersion = "6.0.0-beta.7";

        if (dependencies["@ionic/angular"]) {
            const ionicVersion = dependencies["@ionic/angular"];

            // If it's a valid version let's check it's greater than highest not supported Ionic major version beta
            if (semver.valid(ionicVersion)) {
                if (CordovaProjectHelper.versionSatisfiesInterval(
                    ionicVersion,
                    highestNotSupportedIonic4BetaVersion,
                    "5.0.0")
                ) {
                    return 4;
                }
                if (CordovaProjectHelper.versionSatisfiesInterval(
                    ionicVersion,
                    highestNotSupportedIonic5BetaVersion,
                    "6.0.0")
                ) {
                    return 5;
                }
                if (semver.gt(ionicVersion, highestNotSupportedIonic6BetaVersion)) {
                    return 6;
                }
            }

            // If it's a valid range we check that the entire range is greater than highest not supported Ionic major version beta
            if (semver.validRange(ionicVersion)) {
                if (CordovaProjectHelper.versionRangeSatisfiesInterval(
                    ionicVersion,
                    highestNotSupportedIonic4BetaVersion,
                    "5.0.0")
                ) {
                    return 4;
                }
                if (CordovaProjectHelper.versionRangeSatisfiesInterval(
                    ionicVersion,
                    highestNotSupportedIonic5BetaVersion,
                    "6.0.0")
                ) {
                    return 5;
                }
                if (semver.ltr(highestNotSupportedIonic6BetaVersion, ionicVersion)) {
                    return 6;
                }
            }

            // Assuming for now that latest version is 6
            if (ionicVersion === "latest" || ionicVersion === "nightly") {
                return 6;
            }
        }
    }