A library for managing environment variables in TypeScript projects.

The library contains five functions, one for asserting non-nullability and four for extracting values with a specific type.

These are the following:

• assertNonNullable,
• extractStringEnvVar,
• extractNumberEnvVar,
• extractIntegerEnvVar,
• extractBooleanEnvVar.

This function acts as a TypeScript assertion for non-nullable values:

• if the provided value is nullable, it throws an error,
• if the provided value is non-nullable, it asserts its type to be non-nullable.

An exemplary usage:

const { A } = process.env;

assertNonNullable('A', A);

This function extracts the string value of an indicated environment variable or throws an error, should the variable be not present.

An example is available below:

const A = extractStringEnvVar('A');

This function extracts the value of an indicated environment variable and casts it to a number. If the variable is not present or the function cannot cast the value into a number, it will throw an error.

Check the usage below:

const A = extractNumberEnvVar('A');

This function extracts the value of an indicated environment variable and casts it to an integer. If the variable is not present or the function cannot cast the value into an integer, it will throw an error.

Check the usage below:

const A = extractIntegerEnvVar('A');

This function extracts the value of an indicated environment variable and casts it to a boolean. If the variable is not present or the function cannot cast the value into a boolean, it will throw an error.

Check the usage below:

const A = extractBooleanEnvVar('A');