Programmatically Validate Environment Variables

Ethan Glover

Last Updated: 2 years ago

1const envVariables = process.env;
2           
3export const envCheck = () => {
4  const defaultVariables = {
5    API_TOKEN: undefined,
6    API_ROOT: 'https://example.com',
7    DATABASE_URL: undefined,
8  };
9           
10  const envVariableKeys = Object.keys(envVariables);
11  const defaultVariableKeys = Object.keys(defaultVariables);
12  const missingKeys = [];
13
14  for (const key of defaultVariableKeys) {
15    if (!envVariableKeys.includes(key) || envVariables[key] === undefined) {
16      missingKeys.push(key);
17    }
18  }
19           
20  if (missingKeys.length > 0) {
21    throw new Error(
22      `Missing the following env variables, add them to .env: ${missingKeys.join(
23      ', '
24    )}`
25  );
26}