xarg

A small tool for validating arguments in JavaScript

$3

npm install xarg --save

$3

Every function will check if passed variable is defined and if it have a value of a specific type.
This will throw an assertion error when values are not valid.

A list of available functions:

* isArguments()
* isArray()
* isArrayBuffer()
* isBoolean()
* isBuffer()
* isDate()
* isDefined()
* isEmpty()
* isError()
* isFinite()
* isFunction()
* isInteger()
* isMap()
* isNaN()
* isNil()
* isNull()
* isNumber()
* isObject()
* isPlainObject()
* isPromise()
* isRegExp()
* isSet()
* isString()
* isSymbol()
* isTypedArray()
* isWeakMap()
* isWeakSet()

To test your arguments you need to pass an object with data. For example:

``js
xarg.isArray({a: [], b:[1,2,3], c: {}})
`

$3

`js
function hello(text, age) {
xarg.isString({text});
xarg.isNumber({age});
}

hello('John', 25); // OK
hello([]); // AssertionError [ERR_ASSERTION]: "text" should be of type String, but got: object
hello('John'); // AssertionError [ERR_ASSERTION]: "age" should be defined
hello('John', 'abc'); // AssertionError [ERR_ASSERTION]: "age" should be of type Number, but got: string
`

#### Example #2

`js
class APIService {
constructor(url) {
xarg.isString({url});
}

post(json) {
xarg.isObject({json});
}
}

const service = new APIService('https://example.com');
service.post({ data: '123' }); // OK

new APIService([]); // AssertionError [ERR_ASSERTION]: "url" should be of type String, but got: object
new APIService({}); // AssertionError [ERR_ASSERTION]: "url" should be of type String, but got: object

const service = new APIService(123); // AssertionError [ERR_ASSERTION]: "age" should be of type Number, but got: string
service.post('123'); // AssertionError [ERR_ASSERTION]: "json" should be of type Object, but got: string

`

$3

Run tests:

npm test

Run tests with code coverage:

npm run test-cov`