TinyValid

TinyValid is a Typescript written validation library providing various lightweight validation functions.

#### Table of Contents:
- How to use
- Tip for Typescript projects
- Validators:
- has
- :small_orange_diamond: isArray
- :small_orange_diamond: isArrayOf
- :small_orange_diamond: isBool
- isDecimal
- isEmpty
- isEmptyArray
- isEmptyObject
- isEmptyString
- isFinite
- isFunc
- isInfinite
- isInteger / isInt
- isNegativeInteger
- :small_orange_diamond: isNil
- isNotArray
- isNotEmptyArray
- isNotEmptyString
- isNotNull
- isNotString
- :small_orange_diamond: isNull
- :small_orange_diamond: isNumber
- isObject
- isPositiveInteger
- :small_orange_diamond: isString
- :small_orange_diamond: isUndefined

How to use

Install the library by running
``
npm install --save tinyvalid
`

You can then import the whole library:
`typescript
import * from 'tinyvalid';
`
or you can import only the validators you need and thus reducing your bundle's final size
`typescript
import { isInteger } from 'tinyvalid/dist/validators/isInteger';
import { isObject } from 'tinyvalid/dist/validators/isObject';
import { isEmptyString } from 'tinyvalid/dist/validators/isEmptyString';
`

$3

Some of the validators make use of type-guards in order to avoid unnecessary type asserting of variables in your code (https://basarat.gitbook.io/typescript/type-system/typeguard#user-defined-type-guards). You can find which validators use type-guards by the orange diamond ( :small_orange_diamond: ) before their name.

Example of type-guards:
`typescript
const username: string | undefined = Math.random() > .5 ? ' tinyuser ': undefined;
let trimmedUsername: string;

// PREFER USING VALIDATORS WITH TYPE-GUARDING...

// isString makes use of type-guards which means the typescript can understand after
// the validator if the variable - username - is of type string or not
if (!isString(username)) {
console.log('username is not a string');
} else {
trimmedUsername = username.trim();
}

// ...INSTEAD OF VALIDATORS WITHOUT TYPE-GUARDING

// isNotString does NOT make use of type-guards
if (isNotString(username)) {
console.log('username is not a string');
} else {

// You'll have to assert the username's type since the compiler doesn't know after
// the validator if the variable - username - is a string or undefined
trimmedUsername = (username).trim();
}
`

Validators

#### has
Returns true if the object has a property with the name value _(The validator is mostly a wrapper function of Object.prototype.hasOwnProperty)_
`typescript
has (object: any, value: string | number | symbol, nilCheck?: boolean)
`
|Parameter|Type|Optional|Default Value|Description|
|--|--|--|--|--|
|object|any|No|-|
|value|string\|number\|symbol|No|-|
|nilCheck|boolean|Yes|true|If set to true the validator will check first if the object is _null_ or _undefined_ and thus avoiding potential errors


#### :small_orange_diamond: isArray
Returns true if the value is an array
`typescript
isArray (value: any)
`
|Parameter|Type|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### :small_orange_diamond: isArrayOf
Returns true if the value is an array and all of its items match the supplied predicate function
`typescript
type Predicate: (value: any) => boolean;

isArrayOf (value: any, predicate: Predicate)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|
|predicate|Predicate|No|-|A function which will run on each element of the array which takes an element as an argument and returns a boolean

Examples:

`javascript
import { isArrayOf, isString, isNotEmptyString } from 'tinyvalid';

const arr = [' ', 'This is a string'];

// Check if the value is an array on strings
// Expected result: true
const arrayOfStrings = isArrayOf(arr, isString);

// Check if the value is an array of non-empty strings
// Expected result: false - since the first element is a string of spaces which after getting
// trimmed by the isNotEmptyString validator will not pass the predicate fuction
const arrayOfNonEmptyStrings = isArrayOf(arr, (val) => isNotEmptyString(val, true));

// Check if the value is an array of strings with less than 20 characters
// Expected Result: true
const arrayOfShortStrings = isArrayOf(arr, (val) => isString(val) && val.length < 20);
`


#### :small_orange_diamond: isBool
Returns true if the value is a boolean
`typescript
isBool (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isDecimal
Returns true if the value is a decimal number
`typescript
isDecimal (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isEmpty
Returns true if the value is null or undefined or an empty string or an empty object or an empty array
`typescript
isEmpty (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isEmptyArray
Returns true if the value is an empty array
`typescript
isEmptyArray (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isEmptyObject
Returns true if the value is an empty object
`typescript
isEmptyObject (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isEmptyString
Returns true if the value is an empty string
`typescript
isEmptyString (value: any, trim?: boolean)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|
|trim|boolean|Yes|true|If set to true the validator will trim the value before checking if it's an empty string


#### isFinite
Returns true if the value is a finite number
`typescript
isFinite (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isFunc
Returns true if the value is a function
`typescript
isFunc (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isInfinite
Returns true if the value is infinity (positive or negative)
`typescript
isInfinite (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isInteger
Returns true if the value is an integer
`typescript
isInteger (value: any)

// Shorthand of isInteger
isInt (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isNegativeInteger
Returns true if the value is a negative integer
`typescript
isNegativeInteger (value: any, includeZero?: boolean)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|
|includeZero|boolean|Yes|false|Returns also true if the value is zero


#### :small_orange_diamond: isNil
Returns true if the value is null or undefined
`typescript
isNil (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isNotArray
Returs true if the value is not an array
`typescript
isNotArray (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|

#### isNotEmptyArray
Returns true if the value is not an empty array
`typescript
isNotEmptyArray (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isNotEmptyString
Returns true if the value is not an empty string
`typescript
isNotEmptyString (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|
|trim|boolean|Yes|true|If set to true the validator will trim the value before checking if it's not an empty string


#### isNotNull
Returns true if the value is not null
`typescript
isNotNull (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isNotString
Returns true if the value is not a string
`typescript
isNotString (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### :small_orange_diamond: isNull
Returns true if the value is null
`typescript
isNull (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### :small_orange_diamond: isNumber
Returns true if the value is a number (and not NaN)
`typescript
isNumber (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### isObject
Returns true if the value is an object
`typescript
isObject (value: any, excludeArrays?: boolean)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|
|excludeArrays|boolean|Yes|true|If set to false the validator will count arrays as objects (since in Javascript the typeof an array returns object)


#### isPositiveInteger
Returns true if the value is a positive integer
`typescript
isPositiveInteger (value: any, includeZero?: boolean)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|
|includeZero|boolean|Yes|false|Returns also true if the value is zero


#### :small_orange_diamond: isString
Returns true if the value is a string
`typescript
isString (value: any)
`
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|


#### :small_orange_diamond: isUndefined
Returns true if the value is undefined
`typescript
isUndefined (value: any)
``
|Parameter|Type (Typescript)|Optional|Default Value|Description|
|--|--|--|--|--|
|value|any|No|-|