Checkoid is a validator library with zero dependencies that allows to combine validator like you would lego piece.
You can create simple validator: Simply pass a function, that either return a value for an error, or nothing if the value is valid.
import { validator } = from 'checkoid';
const isEmail = validator((value) => {
return /@/.test(value);
}, 'value is an email');
const isNotGmail = validator((value) => {
return !/gmail.com/.test(value);
}, 'value is not a gmail adress');
isEmail.check('[email protected]'); // undefined
isNotGmail.check('[email protected]');
// [{ predicate: 'value is not a gmail adress', valid: false, value: '[email protected]' }]
isEmail.check('whatever');
// [{ predicate: 'value is an email', valid: false, value: 'whatever' }]
isNotGmail.check('whatever');
// [{ predicate: 'value is not a gmail adress', valid: false, value: 'whatever' }]
And then combine them with and
const isEmailNotFromGMail = isEMail.and(isNotGmail);
isEmailNotFromGMail.check('whatever');
// [
// { predicate: 'value is an email', valid: false, value: 'whatever' },
// { predicate: 'value is not a gmail adress', valid: false, value: '[email protected]' }
// ]
isEmailNotFromGMail.check('[email protected]');
// [{ predicate: 'value is not a gmail adress', valid: false, value: '[email protected]' }]
isEmailNotFromGMail.check('[email protected]'); // undefined
Or with or
const isEmpty = validator((value) => {
return !!value;
}, 'value is empty');
const isOptionalEmail = isEmail.or(isEmpty);
isOptionalEmail.check(''); // undefined
isOptionalEmail.check('[email protected]'); // undefined
isOptionalEmail.check('invalid mail');
// [
// { predicate: 'value is an email', valid: false, value: 'invalid mail' },
// { predicate: 'value is empty', valid: false, value: 'invalid mail' }
// ]
Even with xor
const hasFoo = validator((value) => {
return !!value.foo;
}, 'value has foo');
const hasBar = validator((value) => {
return !!value.bar;
}, 'value has bar');
const hadFooOrBarButNotBoth = hasFoo.xor(hasBar);
isOptionalEmail.check({ foo: true }); // undefined
isOptionalEmail.check({ bar: true }); // undefined
isOptionalEmail.check({});
// [
// { predicate: 'value has foo', valid: false, value: {} },
// { predicate: 'value has bar', valid: false, value: {} }
// ]
isOptionalEmail.check({ foo: true, bar: true });
// [
// { predicate: 'value has foo', valid: true, inverted: true, value: {} },
// { predicate: 'value has bar', valid: true, inverted: true, value: {} }
// ]
You can invert a validator with not.
const isNoEmail = isEmail.not();
isNoEmail.check('whatever'); // undefined
isNoEmail.check('[email protected]');
// [{ predicate: 'value is an email', valid: true, inverted: true, value: '[email protected]' }]
You can validate object too
import { shape } = from 'checkoid';
const isGreaterThan = length => validator(value => {
return value && value.length > length;
}, `value is at least ${length} characters long`);
// objectValidator takes an object of other validator and returns a validator
const validateUser = shape({
email: isEmail.or(isEmpty),
password: isGreaterThan(8),
});
validateUser.check({ email: '[email protected]', password: 'shouldnotdisplaythis' }) // undefined
validateUser.check({ email: '[email protected]', password: 'secret' })
// [{ key: ['password'], predicate: 'value is at least 8 characters long', valid: false, value: 'secret' }]
validateUser.check('Hi I am John a valid user')
// [
// { predicate: 'value is an object', valid: false, value: 'Hi I am John a valid user' },
// { key: ['password'], predicate: 'value is at least 8 characters long', valid: false, value: undefined' },
// ]
Or array
import { arrayOf } from 'checkoid';
// listValidator take any validator and apply it to a list of value
const isEmailList = arrayOf(isEmail);
isEmailList.check([]); // undefined
isEmailList.check(['[email protected]', '[email protected]']); // undefined
isEmailList.check(['[email protected]', 'I am a valid email', '[email protected]']);
// [{ key: [1], predicate: 'value is an email', valid: false, value: 'I am a valid email' }]
isEmailList.check('I am an email list'); // [{ predicate: 'value is an array', valid: false, value: 'I am an email list' }]
Or array of object
import { arrayOf } from 'checkoid';
const isUserList = arrayOf(validateUser);
isUserList.check([]); // undefined
isUserList.check([
{ email: '[email protected]', password: 'shouldnotdisplaythis' },
{ email: '[email protected]', password: 'mySecretPassword' },
]); // undefined
isUserList.check([
{ email: '[email protected]', password: 'shouldnotdisplaythis' },
'I am an user',
{ email: '[email protected]', password: '1234' },
]);
// [
// { key: [1], mesage: 'value is an object', valid: false, value: 'I am an user' },
// { key: [2, 'password'], predicate: 'value is at least 8 characters long', valid: false, value: '1234' },
// ]
In short all validators can be combined together, and you will always get back a Validator.
It is also possible to create asynchronous Validator
import { asyncValidator } = from 'checkoid';
const doesUserIdExists = asyncValidator(async value => {
const user = await fetchUser(value);
return !!user;
}, 'There is a user with this id');
// with an asynchronous validator the check method return a promise
await doesUserIdExists.check('badId');
// [{ predicate: 'There is a user with this id', valid: false, value: 'badId' }]
await doesUserIdExists.check('goodId'); // undefined'
Asynchronous Validators can be combined exactly like synchronous ones. They can even be combined with synchronous Validator. Simply as soon as an asynchronous Validator get combined with other synchronous Validator, the resultant validator will automatically become asynchronous.
Function to create a validator. It takes a simple validation function that take a value and returns either undefined when the value is valid or an invalid message when the value is not.
import { validator } from 'checkoid';
const isEqual10 = validator(value => value === 10 ? undefined : 'value must be 10');
isEqual10.check(10) // undefined
isEqual10.check(5) // [{ predicate: 'value must be 10', value: 5 }]
Function to create a validator from an async validation function. It takes a simple validation async function that takes a value and returns a promise holding either undefined when the value is valid or an invalid message when the value is not.
import { asyncValidator } from 'checkoid';
const doesUserIdExists = asyncValidator(async value => {
const user = await fetchUser(value);
if (user) {
return;
}
return 'There is no user with this id';
});
// with an async validator the check method return a promise
await doesUserIdExists.check('badId');
// [{ predicate: 'There is no user with this id', value: 'badId' }]
await doesUserIdExists.check('goodId'); // undefined'
All exported value in checkoid are either Validator or function that returns a Validator. The validator object possess the following methods.
Takes a value and either returns undefined if it pass the validation or an array of object describing the issues otherwise. The array contains an object for each validation function that returned an issue.
If the validator is async, the result will get wrapped inside a promise
It possess the following preoperty :
- predicate: The message returned by the validation function
- value: The value that has been tested. In the case of a shape or arrayOf validator this will be the targeted nested value and not the whole object or array.
- key: Optional, the key of the value being tested if applyable
Takes another validator and returns a new validator that apply the validations of both validator. All error will get concatenated.
import { isGt, isNumber } from 'checkoid';
const isGt3 = isGt(3).and(isNumber);
isGt3.check(4); // undefined
isGt3.check(1);
// [
// { predicate: 'value must be greater than 3', value: 1 },
// ]
isGt3.check('four);
// [
// { predicate: 'value must be greater than 3', value: 'four' },
// { predicate: 'value must be a number', value: 'four' },
// ]
Takes another validator and returns a new validator that apply the validations of both validator. It will only return the errors if both validator are invalid. If one of the two pass, the error of the other one will get ignored.
import { validator, match } from 'checkoid';
const isEmail = validator((value) => {
if (/@/.test(value)) {
return;
}
return 'value is an email';
});
const isEmpty = validator((value) => {
if (!value) {
return 'value is empty';
}
});
const isOptionalEmail = isEmail.or(isEmpty);
isOptionalEmail.check(''); // undefined
isOptionalEmail.check('[email protected]'); // undefined
isOptionalEmail.check('invalid mail');
// [
// { predicate: 'value is an email', valid: false, value: 'invalid mail' },
// ]
Takes a function that receives all error object for the given validator and allow to return a new message. This allows to change the message part of the return value. This function returns a new validator.
const isEmail = match(/@/).format(({ message, value }) => `value: "${value}" is a valid email`);
isEmail.check('[email protected]'); // undefined
isEmail.check('whatever');
// [{ predicate: 'value: "whatever" is a valid email', valid: false, value: 'whatever' }]
Takes a function that will be applyed to the tested value before the validation function. This allows to sanitize the value. This function returns a new validator.
import { hasLengthGt } from 'checkoid';
const isLongerThan8 = hasLengthGt(8).beforeHook(value => value.trim());
isLongerThan8.check(' hey ');
// [{ predicate: 'value has a length greater than 8', valid: false, value: 'hey' }]
Advanced usage only. This works like format, but instead of allowing to change the message, it allows to changes the whole error object. If you decide you need this, keep the message, value and key property on the object.
Internal function please ignore. If you use this I sure hope you know what you are doing. Otherwise things will break.
Internal function please ignore. If you use this I sure hope you know what you are doing. Otherwise things will break.
Checkoid provides the following basic validator to check basic type. Thy are stright forward.
- isNumber: check the value is a number
- isString: check the value is a string
- isBoolean: check the value is a boolean
- isObject: check the value is a object
- isArray: check the value is a array
- isTrue: check the value is
true
- isFalse: check the value is
false
Checkoid provides the following validator factory function that returns validator.
Take a minimum value and returns a validator that check if the value is greater than the given minimum value
import { isGt } from 'checkoid';
const isGreaterThanFive = isGt(5);
isGreaterThanFive.check(6); // undefined
isGreaterThanFive.check(1); // [{ predicate: 'value is greater than 5', value: 1 }]
Take a minimum value and returns a validator that check if the value is greater or equal than the given minimum value
import { isGte } from 'checkoid';
const isAtLeastFive = isGte(5);
isAtLeastFive.check(6); // undefined
isAtLeastFive.check(1); // [{ predicate: 'value is at least 5', valid: false, value: 1 }]
Take a maximum value and returns a validator that check if the value is less than the given maximum value
import { isLt } from 'checkoid';
const isLessThanFive = isLt(5);
isLessThanFive.check(1); // undefined
isLessThanFive.check(6); // [{ predicate: 'value is less than 5', valid: false, value: 6 }]
Take a maximum value and returns a validator that check if the value is less or equal to the given maximum value
import { isLte } from 'checkoid';
const isLessThanFive = isLte(5);
isLessThanFive.check(1); // undefined
isLessThanFive.check(6); // [{ predicate: 'value is at most 5', valid: false, value: 6 }]
Take a regex and returns a validator that check if the value match it
import { match } from 'checkoid';
const isEMail = match(/@/);
isEmail.check('[email protected]'); // undefined
isEmail.check('whatever');
// [{ predicate: 'value match pattern /@/', valid: false, value: 'whatever' }]
Take a number and returns a validator that check that the value as a length of the given number.
import { hasLengthOf } from 'checkoid';
const hasLengthOfThree = hasLengthOf(3);
hasLengthOfThree.check([1, 2, 3]); // undefined
hasLengthOfThree.check([]); // [{ predicate: 'value has a length of 3', valid: false, value: [] }]
Take a number and returns a validator who check that the value as a length greater than the given number.
import { hasLengthGt } from 'checkoid';
const isLongerThanThree = hasLengthGt(3);
isLongerThanThree.check([1, 2, 3, 4]); // undefined
isLongerThanThree.check([1, 2, 3]); // [{ predicate: 'value has a length greater than 3', valid: false, value: [1, 2, 3] }]
Take a number and returns a validator who check that the value as a length greater or equal to the given number.
import { hasLengthGte } from 'checkoid';
const hasLengthGteThree = hasLengthGte(3);
hasLengthGteThree.check([1, 2, 3, 4]); // undefined
hasLengthGteThree.check([1, 2, 3]); // undefined
hasLengthGteThree.check([1, 2]); // [{ predicate: 'value has a length of at least 3', valid: false, value: [1, 2] }]
Take a number and returns a validator who check that the value as a length smaller than the given number.
import { hasLengthLt } from 'checkoid';
const isShorterThanThree = hasLengthLt(3);
isShorterThanThree.check([1, 2]); // undefined
isShorterThanThree.check([1, 2, 3, 4]); // [{ predicate: 'value has a length less than 3', valid: false, value: [1, 2, 3, 4] }]
Take a number and returns a validator who check that the value as a length smaller or equal to the given number.
import { hasLengthLte } from 'checkoid';
const hasLengthLteThree = hasLengthLte(3);
hasLengthLteThree.check([1, 2]); // undefined
hasLengthLteThree.check([1, 2, 3]); // undefined
hasLengthLteThree.check([1, 2, 3, 4]);
// [{ predicate: 'value has a length of at most 3', valid: false, value: [1, 2, 3, 4] }]
Take a validator and returns a new validator that apply it to every value in a given array.
import { arrayOf } from 'checkoid';
const isArrayOfNumber = arrayOf(isNumber);
isArrayOfNumber.check([1, 2, 3]); // undefined
isArrayOfNumber.check([1, "deux", 3]);
// [
// {
// key: [1],
// predicate: "value is a number",
// valid: false,
// value: "deux",
// },
// ]
isArrayOfNumber.check(null);
// [
// {
// predicate: "value must be an array",
// valid: false,
// value: null,
// },
// ]
Takes a spec object (an object with key / validator pair) and returns a validator that apply each validators to the corresponding object property. It also check that the passed value is an object
import { shame, match, hasLengthGt } from 'checkoid';
const isEmail = match(/@/);
const validateUser = shape({
email: isEmail,
password: hasLengthGt(8),
});
validateUser.check({ email: '[email protected]', password: 'shouldnotdisplaythis' }) // undefined
validateUser.check({ email: '[email protected]', password: 'secret' })
// [{ key: ['password'], predicate: 'value has a length greater than 8', valid: false, value: 'secret' }]
validateUser.check('Hi I am John a valid user')
// [{ predicate: 'value is an object', valid: false, value: 'Hi I am John a valid user' }]
shape also takes an exact boolean as second argument. When set to true, shape will also ensure that there is no key that is not tested by a validator.
import { shape } from 'checkoid';
const validateUser = shape({
email: isEmail,
password: hasLengthGt(8),
}, true);
validateUser.check({ email: '[email protected]', password: 'shouldnotdisplaythis' }) // undefined
validateUser.check({ email: '[email protected]', password: 'shouldnotdisplaythis', foo: 'bar', bar: 'baz' })
// [{
// predicate: "Value accept only the following keys: email, password",
// valid: false,
// value: {
// email: '[email protected]'
// password: 'shouldnotdisplaythis'
// foo: 'bar',
// bar: 'baz',
// },
// }]
make install
Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.
Please make sure to update tests as appropriate.
make test
To learn more about the contributions to this project, consult the contribution guide.
Checkoid is licensed under the MIT License, courtesy of Marmelab.