As-Is
Description
As-Is contains two modules.
- Is - Type predicates for checking values are of certain types.
- As - Asserting values are of a certain type using the above predicates.
Usage
Using npm:
$ npm i -g npm
$ npm i as-is
In Javascript:
// Load the As and Is
var { As, Is } = require('@dec-land/as-is');
// Load them seperately
var As = require('@dec-land/as-is/as');
var Is = require('@dec-land/as-is/is');
In Typescript
// Load the As and Is
import { Is, As } from '@dec-land/as-is';
// Load them seperately
import As from '@dec-land/as-is/As';
import Is from '@dec-land/as-is/Is';
Examples
In Examples
import Is from '@dec-land/as-is/Is';
Is.number(5) // true
Is.number('test'); // false
Is.arrayOf([5, 10], Is.integer) // true
Is.arrayOf(['a', 'b'], Is.integer); // false
Is.date('date') // false
Is.date(new Date()); // true
// etc...
As Examples
import { As, Is } from '@dec-land/as-is';
let a: unknown = 'test'; // Here we have an unknown string
// console.log(a.split(',')); Split does not exist on type unknown
As.string(a); // Assert the a as a string, if it isn't an error will be thrown.
console.log(a.split(',')); // Now works as flow wouldn't reach here unless a is a string
let b: unknown = [new Date(), new Date()]; // Here we have an unknown array of dates.
// b.map((date) => console.log(date.toLocaleString())); // Property 'map' does not exist on type 'unknown'.
As.arrayOf(b, Is.date); // Assert that b is an array of dates. If not an error will be thrown
b.map((date) => console.log(date.toLocaleString())); // Works fine
// etc...
Why As-Is?
As-Is offers the following predicates that can be used to check or assert whether a value is of a specific type.
- number
- integer
- string
- boolean
- primitive
- nonPrimitive
- date
- json
- array
- readonlyArray
- readonlyArrayOf
- object
- objectWithProperties
- function
Tests
Tests are included for As and Is. These can be ran using:
$ npm test
6 Aug 23, 2022
3 May 18, 2022
4 May 3, 2022
14 Jan 3, 2023
4 Sep 29, 2022
8 Mar 27, 2022
16 Jun 11, 2022
3 May 30, 2022
4 Feb 17, 2022
82 Dec 7, 2022