Getting The Most Out Of TypeScript - Union Types

TypeScript has rapidly grown in popularity in the last few years, and with good reason. It takes a rather flexible language in JavaScript, and fixes one of the big weaknesses of the language, being descriptive typing, with very little compromise having to be made.

However with that increase in popularity comes a big challenge, how to use the language to its full potential. That’s a big challenge. I’m learning some new feature, or way to use TypeScript, almost every week.

A large percentage of TypeScript users come from an Object Oriented background, and therefore naturally draw parallels between TypeScript and the OOP languages they used, particularly languages like Java and C#. However, this mindset can lead to us overlooking very useful features of TypeScript. With this article, I hope to demonstrate how TypeScript differs from those languages, and how we have to change our thinking to extract more from the language.

It’s not about Classes.

First thing’s first, TypeScript is not OOP. TypeScript provides the ability to add Types, which in their own words:

provide a way to describe the shape of an object […] allowing TypeScript to validate that your code is working correctly

Classes exist in JavaScript already. Therefore you can utilise classes in TypeScript too. But Classes are not Types. Classes can, and usually do, define behaviour. Types do not. Types are simply a contract.

A seemingly simple problem

I’ve encountered a few problems over the past few weeks that have demonstrated good uses of Union Types. I will start with a seemingly simple problem:

In my system I am writing, I have two types of Authentication, one for systems, and one for users. I have two different ways of dealing with this, and two different places to look up accounts. It is therefore important I establish which of account it is. My authentication middleware does this work for me, and adds the information to the request for use later on in the pipeline.

#pburgess #tech #typescript

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Getting The Most Out Of TypeScript - Union Types

Arvel Parker

1593156510

Basic Data Types in Python | Python Web Development For Beginners

At the end of 2019, Python is one of the fastest-growing programming languages. More than 10% of developers have opted for Python development.

In the programming world, Data types play an important role. Each Variable is stored in different data types and responsible for various functions. Python had two different objects, and They are mutable and immutable objects.

Table of Contents hide

I Mutable objects

II Immutable objects

III Built-in data types in Python

Mutable objects

The Size and declared value and its sequence of the object can able to be modified called mutable objects.

Mutable Data Types are list, dict, set, byte array

Immutable objects

The Size and declared value and its sequence of the object can able to be modified.

Immutable data types are int, float, complex, String, tuples, bytes, and frozen sets.

id() and type() is used to know the Identity and data type of the object

a**=25+**85j

type**(a)**

output**:<class’complex’>**

b**={1:10,2:“Pinky”****}**

id**(b)**

output**:**238989244168

Built-in data types in Python

a**=str(“Hello python world”)****#str**

b**=int(18)****#int**

c**=float(20482.5)****#float**

d**=complex(5+85j)****#complex**

e**=list((“python”,“fast”,“growing”,“in”,2018))****#list**

f**=tuple((“python”,“easy”,“learning”))****#tuple**

g**=range(10)****#range**

h**=dict(name=“Vidu”,age=36)****#dict**

i**=set((“python”,“fast”,“growing”,“in”,2018))****#set**

j**=frozenset((“python”,“fast”,“growing”,“in”,2018))****#frozenset**

k**=bool(18)****#bool**

l**=bytes(8)****#bytes**

m**=bytearray(8)****#bytearray**

n**=memoryview(bytes(18))****#memoryview**

Numbers (int,Float,Complex)

Numbers are stored in numeric Types. when a number is assigned to a variable, Python creates Number objects.

#signed interger

age**=**18

print**(age)**

Output**:**18

Python supports 3 types of numeric data.

int (signed integers like 20, 2, 225, etc.)

float (float is used to store floating-point numbers like 9.8, 3.1444, 89.52, etc.)

complex (complex numbers like 8.94j, 4.0 + 7.3j, etc.)

A complex number contains an ordered pair, i.e., a + ib where a and b denote the real and imaginary parts respectively).

String

The string can be represented as the sequence of characters in the quotation marks. In python, to define strings we can use single, double, or triple quotes.

# String Handling

‘Hello Python’

#single (') Quoted String

“Hello Python”

# Double (") Quoted String

“”“Hello Python”“”

‘’‘Hello Python’‘’

# triple (‘’') (“”") Quoted String

In python, string handling is a straightforward task, and python provides various built-in functions and operators for representing strings.

The operator “+” is used to concatenate strings and “*” is used to repeat the string.

“Hello”+“python”

output**:****‘Hello python’**

"python "*****2

'Output : Python python ’

#python web development #data types in python #list of all python data types #python data types #python datatypes #python types #python variable type

Christa Stehr

1599315360

Nominal typing in Typescript

Nominal & structural typing

Type systems are typically categorized as either structural or nominal. Languages like Java and Scala have primarily nominal type systems, whereas a language like Typescript has a structural type system. Let’s take a brief look at both systems.

Nominal Typing

In a nominal typing system, type compatibility is checked using the name of the types. If they do not have the same name, then they are not compatible; end of story. **If **Typescript had a nominal typing system the type check for the last line would fail:

Image for post

Structural typing

Typescript uses structural typing to decide whether two types are compatible with one another or not. What do we mean by structural typing? Well, let’s consider the following code snippet:

Image for post

To determine whether the type of the constant color(RGBA) is compatible with the type of serializeColor’s parameter x(RGB) the type system must verify that each member of RGB has a corresponding compatible member in RGBA. In this case, RGB has a single member color for which RGBA has a corresponding member with the same type — [number, number, number] — and so it passes the type check. Notice how the type system ignores the additional members that exist on RGBA (alpha).

#typescript #type-safe #type-systems

Reid Rohan

1625887907

Getting Started With TypeScript Built-in Utility Types Part 1

Table of Contents [ hide ]

A short introduction to utility types
About the syntax
Note on availability
Partial
Required
Readonly
Record<Keys, Type>
Pick<Type, Keys>
Omit<Type, Keys>
Exclude<Type, ExcludedUnion>
Extract<Type, Union>
Conclusion: Getting started with TypeScript built-in utility types part 1

TypeScript can be difficult to understand for many developers. One area causing troubles are advanced types. Part of this area are utility types built in TypeScript. They can help you create new types from existing. In this article, you will learn how some of these utility types work and how to use them.

A short introduction to utility types

TypeScript provides a powerful system for working with types. There are the basic types you already know from JavaScript. For example, types such as number, string, boolean, object, symbol, null, undefined. This is not all TypeScript offers. On top of these types are also built-in utility types.

It is sometimes also these utility types that can be the most difficult to understand for developers coming to TypeScript. This is especially true when you see these types for the first time. The good news is that these types are actually not that difficult, if you understand one important thing.

All those built-in utility types are actually simple functions, function you already know from JavaScript. Main difference here is that these functions, these utility types, work only with types. What these functions do is they transform types from one type to another. They take some input.

This input is some type you are starting with. You can also provide multiple types. What comes next is that the function transforms that input and return appropriate output. This output are also some types. The type of transformation that happens depends on the utility type you use.

There are currently around 17 utility types: Partial<Type>, Required<Type>, Readonly<Type>, Record<Keys,Type>, Pick<Type, Keys>, Omit<Type, Keys>, Exclude<Type, ExcludedUnion>, Extract<Type, Union>, NonNullable<Type>, Parameters<Type>, ConstructorParameters<Type>, ReturnType<Type>, InstanceType<Type>, ThisParameterType<Type>, OmitThisParameter<Type>, ThisType<Type> and Intrinsic String Manipulation Types. Let’s start with the first eight.

#typescript #development #language #typescript

websolution stuff

1627019580

How to Get Current URL in Laravel

In this small post we will see how to get current url in laravel, if you want to get current page url in laravel then we can use many method such type current(), full(), request(), url().

Here i will give you all example to get current page url in laravel, in this example i have used helper and function as well as so let’s start example of how to get current url id in laravel.

https://websolutionstuff.com/post/how-to-get-current-url-in-laravel

https://websolutionstuff.com/post/laravel-signature-pad-example

#how to get current url in laravel #laravel get current url #get current page url in laravel #find current url in laravel #get full url in laravel #how to get current url id in laravel

Lambert Goldner

1626081635