Parsing numbers, booleans and null values

[wjstraver]

Hi,

First off, I like how easy it is with this package to import .env values into my project. However, I've noticed in my test projects, I'll would like it if true/false are parsed as boolean, numbers are correctly parsed, empty values are null or undefined instead of an empty string.

Right now I add the following code to my projects:

import {config} from "https://deno.land/x/dotenv@v0.5.0/mod.ts";

type EnvValue = null|number|boolean|string

type EnvObject = {
    [key: string]: EnvValue
}

export const env = Object.entries(config())
    .reduce((envObj: EnvObject, [key, value]: [string, string]) => {
        if(value === "" || value === "null") {
            envObj[key] = null;
        } else if (/^true|false$/i.test(value)) {
            envObj[key] = JSON.parse(value.toLowerCase());
        } else if (/^(\d*\.?\d+)$/.test(value)) {
            envObj[key] = parseFloat(value);
        } else {
            envObj[key] = value;
        }

        return envObj;
    }, {});

How would you look at the idea of implementing this something along the line of:

config({parseTypes: true});

[pietvanzoen]

Hi there! Thanks for the kind words. Apologies for the delayed reply.

This is an interesting idea and something people have mentioned before.

The tricky thing to get around is that as far as the shell is concerned environment variables are always strings. Deno.env.set respects this and will error if given anything but a string. So the export option of config would be incompatible with the parseTypes option. I'd rather keep things consistent between how config() returns variables and how Deno.env.get returns variables.

However, if you'd like to publish a helper module with what you have (similar to dotenv-expand) I'd be happy to include it in the docs.

[wjstraver]

Hi,

I understand why you would like to stay true to the environment variables by keeping everyting as strings. I'll take a look in creating a helper module myself. Maybe adding something like getEnv('ENV_NAME', 'default value') or other small features as well.

Will let you know when/if I have something!

[pietvanzoen]

Doing some housekeeping and closing this issue. Feel free to comment if you have any updates.

Cheers