env-validate/src/env-validate.js

Validates your environment variables are set at runtime.

const fs = require('fs');

const extractEnvVarNames = require('./extract-env-var-names');
const findTemplatePath = require('./find-template-path');

const envValidate = ({ onError = null, optionals = [], templatePath = findTemplatePath() } = {}) => {
  const fileContent = fs.readFileSync(templatePath, 'utf-8');

  const expectedEnvVarNames = extractEnvVarNames(fileContent).filter(str => !optionals.includes(str));

  expectedEnvVarNames.forEach(envVarName => {
    if (!process.env[envVarName]) {
      if (onError) {
        return onError(envVarName);
      }

      throw `Environment variable '${envVarName}' is missing.`;
    }
  });
};

module.exports = envValidate;