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
  • 🔸 isArray
  • 🔸 isArrayOf
  • 🔸 isBool
  • isDecimal
  • isEmpty
  • isEmptyArray
  • isEmptyObject
  • isEmptyString
  • isFinite
  • isFunc
  • isInfinite
  • isInteger / isInt
  • isNegativeInteger
  • 🔸 isNil
  • isNotArray
  • isNotEmptyArray
  • isNotEmptyString
  • isNotNull
  • isNotString
  • 🔸 isNull
  • 🔸 isNumber
  • isObject
  • isPositiveInteger
  • 🔸 isString
  • 🔸 isUndefined

How to use

Install the library by running

npm install --save tinyvalid

You can then import the whole library:

import * from 'tinyvalid';

or you can import only the validators you need and thus reducing your bundle's final size

import { isInteger } from 'tinyvalid/dist/validators/isInteger';
import { isObject } from 'tinyvalid/dist/validators/isObject';
import { isEmptyString } from 'tinyvalid/dist/validators/isEmptyString';

Tip for Typescript projects

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 ( 🔸 ) before their name.

Example of type-guards:

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 = (<string>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)

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

🔸 isArray

Returns true if the value is an array

isArray (value: any)

Parameter	Type	Optional	Default Value	Description
value	any	No	-

🔸 isArrayOf

Returns true if the value is an array and all of its items match the supplied predicate function

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:

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);

🔸 isBool

Returns true if the value is a boolean

isBool (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isDecimal

Returns true if the value is a decimal number

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

isEmpty (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isEmptyArray

Returns true if the value is an empty array

isEmptyArray (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isEmptyObject

Returns true if the value is an empty object

isEmptyObject (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isEmptyString

Returns true if the value is an empty string

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

isFinite (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isFunc

Returns true if the value is a function

isFunc (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isInfinite

Returns true if the value is infinity (positive or negative)

isInfinite (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isInteger

Returns true if the value is an integer

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

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

🔸 isNil

Returns true if the value is null or undefined

isNil (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isNotArray

Returs true if the value is not an array

isNotArray (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isNotEmptyArray

Returns true if the value is not an empty array

isNotEmptyArray (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isNotEmptyString

Returns true if the value is not an empty string

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

isNotNull (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isNotString

Returns true if the value is not a string

isNotString (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

🔸 isNull

Returns true if the value is null

isNull (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

🔸 isNumber

Returns true if the value is a number (and not NaN)

isNumber (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

isObject

Returns true if the value is an object

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

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

🔸 isString

Returns true if the value is a string

isString (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-

🔸 isUndefined

Returns true if the value is undefined

isUndefined (value: any)

Parameter	Type (Typescript)	Optional	Default Value	Description
value	any	No	-