1621434673
Conditional Types in Typescript - No BS TS #18
Turns out you can define types conditionally based on the type check against a different type. Let’s try it out on a fetch function that optionally takes a callback and can return either a void or a promise based on that callback.
- 00:00 Introduction
- 00:18 What are conditional types?
- 02:15 Importing libraries
- 03:15 fetchPokemon with conditionals
- 08:23 fetchPokemon with overloading
- 11:14 Outroduction
Conditional Types page: https://www.typescriptlang.org/docs/handbook/2/conditional-types.html
Code: https://github.com/jherr/no-bs-ts/tree/master/episode-18
#typescript
What is GEEK
Buddha Community
1654588030
The Definitive Guide to TypeScript & Possibly The Best TypeScript Book
TypeScript Deep Dive
I've been looking at the issues that turn up commonly when people start using TypeScript. This is based on the lessons from Stack Overflow / DefinitelyTyped and general engagement with the TypeScript community. You can follow for updates and don't forget to ★ on GitHub 🌹
Reviews
- Thanks for the wonderful book. Learned a lot from it. (link)
- Its probably the Best TypeScript book out there. Good Job (link)
- Love how precise and clear the examples and explanations are! (link)
- For the low, low price of free, you get pages of pure awesomeness. Chock full of source code examples and clear, concise explanations, TypeScript Deep Dive will help you learn TypeScript development. (link)
- Just a big thank you! Best TypeScript 2 detailed explanation! (link)
- This gitbook got my project going pronto. Fluent easy read 5 stars. (link)
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- Thanks @basarat for the TypeScript Deep Dive Book. Help me a lot with my first TypeScript project. (link)
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- A book not only for typescript, a good one for deeper JavaScript knowledge as well. link
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1621434673
Conditional Types in Typescript - No BS TS #18
Turns out you can define types conditionally based on the type check against a different type. Let’s try it out on a fetch function that optionally takes a callback and can return either a void or a promise based on that callback.
- 00:00 Introduction
- 00:18 What are conditional types?
- 02:15 Importing libraries
- 03:15 fetchPokemon with conditionals
- 08:23 fetchPokemon with overloading
- 11:14 Outroduction
Conditional Types page: https://www.typescriptlang.org/docs/handbook/2/conditional-types.html
Code: https://github.com/jherr/no-bs-ts/tree/master/episode-18
#typescript
1636240140
What Is The Main Difference Of TYPES Vs INTERFACES in TypeScript
TypeScript has two ways of declaring structures of your objects in the form of #types (type aliases) and #interfaces.
In this lesson we will look at the technical differences between these two, when you should use which, along with real world #TypeScript code analysis, and community thoughts
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
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
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:
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:
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