React Native env accessor and version name displayer

helpers\accessEnv.ts

/*****************************************************************************************
 * Accesses a variable inside of .env file and cache for later usage; throws an error if its not found.
 *
 * caching the values to improve the performance.
 *
 * Usage:
 *
 * import accessEnv from "helpers/accessEnv";
 *
 * const redirectionHost = accessEnv("MAJOR_VERSION", 1);
 ****************************************************************************************/
import Config from "react-native-config";

const cache: Record<string, string> = {};

const accessEnv = (key: string, defaultValue?: string | number): any => {
    // If the .env variable is not declared
    if (![key in Config]) {
        if (defaultValue) {
            return defaultValue;
        }
        throw new Error(`${key} not found in .env`);
    }

    // If returned as undefined
    if (Config[key] === undefined) {
        if (defaultValue) {
            return defaultValue;
        }
        throw new Error(`${key} not found in .env`);
    }

    if (cache[key]) {
        return cache[key];
    }

    cache[key] = Config[key];

    return Config[key];
};

export default accessEnv;

utils\core.ts

import accessEnv from "helpers/accessEnv";

/**
 * Checks if the entity is undefined or not
 * @param state - Target entity
 */
export const isUndefined = (state: any): boolean => typeof state === "undefined";

/**
 * Returns version name of the app
 */
export const getAppVersionName = (): string => {
    let version = `v.${accessEnv("MAJOR_VERSION")}.${accessEnv(
        "MINOR_VERSION",
    )}.${accessEnv("PATCH_VERSION")}`;
    if (!isUndefined(accessEnv("PRE_RELEASE", undefined))) {
        version = version.concat(`-${accessEnv("PRE_RELEASE")}`);
    }

    return version;
};