What does it do?

• Adds type overload to env-helper functions so that they are typed correctly according to the arguments passed to it.
• Update examples to be typed (.ts files only)
  This edit caused false positive regarding code duplication
• Updated template files to be typed (.ts files only)

Why is it needed?

Using strict typescript would give error on code below since typing said foo could be string | undefined.

function printFoo(value: string) {
  console.log(value);
}

const foo = env("FOO", "bar");

// Before
printFoo(foo); //  Type 'undefined' is not assignable to type 'string'.(2345)

// After
printFoo(foo); // No error

Added same type hint for all the other env.<method> methods:

• int
• float
• bool
• json
• array
• date
• oneOf

How to test it?

Hovered the functions to see type definition.

Related issue(s)/PR(s)

N/A