dotenv guards
guards functions for dotenv package
installation
npm i dotenv dotenv-guards
usage
import { numberGuard } from 'dotenv-guards';
const jobsAsNumber = numberGuard(process.env.jobs, 2); // return 2 if jobs is not a number
Available guards
-
numberGuard
- parse a string to a number. -
enumGuard
- parse a string to an enum. -
booleanGuard
- parse a string to a boolean. -
arrayGuard
- parse a string to an array. -
string
- parse string and execute matchers.
Custom guards
In case if you want to define custom guards - you can use define
and revoke
functions.
Example:
import { define, revoke } from 'dotenv-guards';
// define new guard
const jsonGuard = define((val: string | undefined) => {
return JSON.parse(val);
});
jsonGuard('{"qwe": true}'); // returns { qwe: true }
revoke(jsonGuard); // remove json guard
jsonGuard('{"qwe": true}'); // TypeError. jsonGuard is revoked
API
number guard
numberGuard(value, fallbackValue, options)
Parameters
-
value
- [string
] - string-like variable. -
options
- [Object
]-
throwOnFinite
- [boolean
] - Throws an error if incoming value parsed toInfinity
. Default isfalse
. -
throwOnNaN
- [boolean
] - Throws an error if incoming value parsed toNaN
. Default isfalse
. -
throwOnUndefined
- [boolean
] - Iftrue
throwing an error if incoming value is undefined. Default isfalse
. -
throwOnSafeInteger
- [boolean
] - Throws an error if incoming value is not safe integer. Default isfalse
.
-
Returns
number
Example:
// process.env.jobs = '2'
numberGuard(process.env.jobs); // returns 2 as number
// process.env.jobs = 'not a number string'
numberGuard(process.env.jobs); // returns 0 as number
// process.env.jobs = 'not a number string'
numberGuard(process.env.jobs, 0, {throwOnSafeInteger: true}); //throws an error
boolean guard
booleanGuard(value, options)
Parameters
- value - [
string
] - string-like variable. -
options
- [Object
]-
fallback
- fallback value if incoming value is not a boolean and cannot parse value to boolean. -
trueSymbols
- [string
] - Array of possible values which will be converted astrue
. Default is['1', 'true']
-
throwOnUndefined
Throw an error if incoming value is undefined, fallback value is not returned, since it returns an error. Default isfalse
. -
throwOnFail
- Throw an error if incoming value is not matching withtrueSymbols
option. Default isfalse
.
-
Returns
boolean
Example:
// process.env.isDebug = 'true'
booleanGuard(process.env.isDebug); // returns true
// process.env.acceptDownloading = 'yes'
booleanGuard(process.env.acceptDownloading, false, {trueSymbols: ['yes']}); // returns true since 'yes' is in the array
enum guard
enum(value, arrayOfPossibleValues, fallbackValue)
Parameters
-
value
- [string
] - string-like variable. -
arrayOfPossibleValues
- [Array<string>
] - Array of possible values. -
fallbackValue
- [string
] - fallback value.
Returns
string
Example:
// process.env.NODE_ENV = 'test'
enumGuard(process.env.NODE_ENV, ['development', 'production'], 'development'); // returns 'development'
// or define more acceptable values
// process.env.NODE_ENV = 'test'
enumGuard(process.env.NODE_ENV, ['development', 'production', 'test'], 'development'); // returns 'test', since 'test' is in the array
array guard
array(value, arrayOfPossibleValues, options)
Parameters
-
value
- [string
] - string-like variable. -
arrayOfPossibleValues
- [Array<string>
] - Iftrue
throwing an error if at least one element is not matched. -
options
- [Object
]-
strict
- [boolean
] - Iftrue
throwing an error if at least one element is not matched. Default isfalse
. -
separator
- [string
] - Parsing separator. Default is,
-
Returns
string
Example:
// process.env.array = 'val1,val2,val3'
arrayGuard(process.env.array, ['val1', 'val2']); // split string by `,` symbol and returns ['val1', 'val2']
// custom separator
// process.env.array = 'val1;val2;val3'
arrayGuard(process.env.array, ['val1', 'val2', 'val3'], {separator: ';'}); // split string by `;` symbol and returns ['val1', 'val2', 'val3']
string guard
string(value, options)
Parameters
-
value
- [string]. Parsing string-like value. -
options
-
fallback
- [string] - fallback value if incoming value is not matched by regex or matcher function. -
throwOnUndefined
- [boolean] - Throw an error if incoming value is undefined, fallback value is not returned, since it returns an error. -
regexp
- [RegExp] - Regexp for incoming value. Returns first match. -
throwOnNullable
- [boolean] - Throw an error if incoming value is null, undefined, empty string or empty array. -
matcher
- [boolean] - Matcher function for incoming value. Returns boolean(is matched incoming string or not). -
throwOnMismatch
- [boolean] - Throw an error if incoming value is not matched by regex or matcher function.
-
Returns
string
Example:
// process.env.token = 'hash123'
stringGuard(process.env.token); // returns hash123
// matcher function
// process.env.token = 'hash123'
arrayGuard(process.env.token, {
matcher: (value) => value.startsWith('hash'),
}); // returns hash123
// miss matching
// process.env.token = 'hash123'
arrayGuard(process.env.token, {
matcher: (value) => value.startsWith('random string'),
fallback: 'qwerty'
}); // returns qwerty, since mismatch
define(fn)
Parameters
-
function
- [Function] - First argument should accepts typestring | undefined
, otherwise it throws anTypeError
returns
Function
revoke(fn)
Parameters
-
function
- [Function] - function reference fromdefine
. It will throw aReferenceError
in case of function is not created fromdefine
.
Returns
void