attempt to try and change environment variables used in .eslintrc.js for CRA dev server without restarting the dev server

get-env-var.js

/* Usage:
const initGetEnv = require('./dev-scripts/get-env-var.js');

const env = initGetEnv({
    useLiveEnv: typeof process.env.USE_LIVE_ENV !== 'undefined'
});

if (env('foobar')) doSomething();

// The idea is that you'd be able to change variables on the fly by editing the .env.live file.

// didn't work inside .eslintrc.js, could work in other contexts.
// for this to work a file needs to not be re-required each time it's used
*/

/* globals process, module */
/* eslint-disable security/detect-object-injection */
const fs = require('fs');

const convertToBool = rawVal => {
    if (typeof rawVal === 'undefined') return false;
    if (typeof rawVal === 'boolean') return rawVal; // good luck to you
    if (rawVal === 'true' || rawVal === '1') return true;
    if (rawVal === 'false' || rawVal === '0') return false;
    if (parseInt(rawVal, 10) + '' === rawVal) {
        return !!parseInt(rawVal, 10);
    }
    if (typeof rawVal !== 'string') {
        console.log('rawVal is not a string.. rawVal:', rawVal);
        return !!rawVal;
    }
};

// if not run from cli, then we don't want to change behavior.
module.exports = function initGetEnv({ useLiveEnv }) {
    return useLiveEnv ? liveEnv : processEnv;
};

const processEnv = varName => convertToBool(process.env[varName]);

const liveEnv = (function liveEnvClosure() {
    // setup liveEnvVars
    const liveEnvVars = {};
    try {
        let dotEnvFileText = false;
        let readEnvFile = false;
        try {
            dotEnvFileText = fs.readFileSync('./.env.live', { encoding: 'utf8' });
            readEnvFile = true;
        } catch (e) {
            console.error(
                'missing /.env.live file. Try adding this to an .env.local file:' +
                    [
                        'echo "ESLINT_FOR_GITLAB_CI=1\\n',
                        'IGNORE_AIRBNB=1\\n',
                        'IGNORE_ACCESSIBILITY=1\\n" | tee .env.live'
                    ].join('\n')
            );
        }

        if (readEnvFile) {
            // console.log('read .env file', dotEnvFileText);
            (dotEnvFileText.match(/[^\r\n]+/g) || []).forEach(function forEachEnvLine(line) {
                if (!line.includes('=') || line.trim().startsWith('#') || line.trim().length < 1)
                    return;
                const [key, value] = line.split('=');
                liveEnvVars[key] = convertToBool(value);
            });
            // console.log('liveEnvVars', liveEnvVars);
        }
        console.log('successfully parsed .env.live file');
    } catch (e) {
        console.log('caught error (probably while trying to parse ./.env.live)', e);
    }

    return function liveEnvCore(varName) {
        if (typeof process.env[varName] !== 'undefined') {
            return processEnv(varName);
        } else {
            return liveEnvVars[varName];
        }
    };
})();