This repo demonstrates an unexpected change between envalid 7.2.2 and 7.3.0
Run npm install to install all the dependencies and npm run build to build the TypeScript source.
Compiled code can be ran with node dist/index.js.
Output with 7.2.2:
typeof env.TEST: object
typeof env.TEST_CUSTOM: object
Output with 7.3.0:
typeof env.TEST: string
typeof env.TEST_CUSTOM: string
On 7.2.2, setting the default value to be {} or an object gives you an object out for the built-in json validator. But on 7.3.0, the default value is passed directly. While the built-in JSON validator is fine with both a string or an object pre 7.3.0, custom validators could potentially break, since default values were ran through the validator.
Trying to set TEST_CUSTOM default value to an object in 7.2.2 will result in a parsing error. Leaving it to a string in 7.2.2 gives you an object out. However, when you upgrade to 7.3.0, you'll get the default values directly, so TEST_CUSTOM is suddenly a string.