Gordon  Taylor

Gordon Taylor

1633367280

Find out Index Signatures in TypeScript

Let’s find what are TypeScript index signatures and when they’re needed.

Table of Contents

  • 1. Why index signature
  • 2. Index signature syntax
  • 3. Index signature caveats
    • 3.1 Non-existing properties
    • 3.2 String and number key
  • 4. Index signature vs Record<Keys, Type>
  • 5. Conclusion

#typescript 

What is GEEK

Buddha Community

Find out Index Signatures in TypeScript

I am Developer

1597488623

Laravel 7 Digital Signature Pad

In this post, i will show you how to create digital signature pad in laravel.

Here, i will guide you step by step to create digital signture pad in laravel. So, follow the following steps and create digital signature pad in laravel.

Laravel Signature Pad Tutorial

Follow below given steps to create laravel digital signature pad app:

  1. Step 1: Install Laravel New App
  2. Step 2: Connect Database To App
  3. Step 3: Create One Model and Migration
  4. Step 4: Add Routes For digital Signature Pad
  5. Step 5: Create Controller by Artisan Command
  6. Step 6: Create Blade View
  7. Step 7: Make Upload Directory
  8. Step 8: Start Development Server

https://www.tutsmake.com/laravel-signature-pad-tutorial-from-scratch/

#laravel digital signature #digital signature implementation in laravel #laravel signature pad #signature pad laravel #digital signature laravel

Gordon  Taylor

Gordon Taylor

1633367280

Find out Index Signatures in TypeScript

Let’s find what are TypeScript index signatures and when they’re needed.

Table of Contents

  • 1. Why index signature
  • 2. Index signature syntax
  • 3. Index signature caveats
    • 3.1 Non-existing properties
    • 3.2 String and number key
  • 4. Index signature vs Record<Keys, Type>
  • 5. Conclusion

#typescript 

Cayla  Erdman

Cayla Erdman

1601549700

What’s New In Typescript 4.0?

Today I am going to talk about new features in Typescript 4.0.

TypeScript 4.0 comes with lots of new features to make JavaScript development easier.

Labeled Tuple Elements

You can label tuple elements.

You can write:

type Range = [start: number, end: number];

to restrict args to have a string and a number.

you can also write:

type Foo = [first: number, second?: string, ...rest: any[]];

to have rest entries in your tuple.

If your tuple has type Foo, then the tuple starts with a number and a string.

Then the rest of the entries can be anything.

Labels don’t require you to name your variables differently when destructuring.

For example, if you have:

function foo(x: [first: string, second: number]) {
  const [a, b] = x;
}

then you can name the destructured variables anything you want.

#software-development #typescript-with-react #typescript #typescript-4 #react native

Shawn  Durgan

Shawn Durgan

1598750220

MongoDB Indexes: Deep Dive, Understanding Indexes.

Getting a performance boost with the best usage of indexes, by understanding what’s the data structure, how it works’s/stored, how is it loaded into memory. How Query optimization make’s decision to select indexes.

_Basic understanding of indexes is required i.e what are indexes, index types, creating them. _https://docs.mongodb.com/manual/indexes/

  • Data Structure
  • Storage on disk
  • Memory Allocation.

Data Structure

Index on a filed/fields is stored in order that we specify using B-Tree data structure. Stored in ordered Let see what does it mean’s and how it help’s.

  • Index is created on the value of the filed referencing to the actual document stored.

Image for post

snipped from: MognoDB university

  • Using B-Tree indexes significantly reduces the number of comparison to find the document.

Image for post

snipped from: MognoDB university

  • Likewise in below picture we can see with index(sky blue line) even adding document still limit the number of document examined in comparison to without index/collscan.

Image for post

snipped from: MognoDB university

Storage On Disk

Let’s see/visualize how the index are stored on disk. Index stored on disk is managed by the database storage engine itself.

  • Uses prefix Index compression- Repeated prefix value is not written, let us see example to understand what it mean’s.
db.getCollection("movieTicket")
.ensureIndex({"showDate":1, "seatNo":1, "status":1});

How the index ({“showDate”:1, “seatNo”:1, “status”:1}) is stored on disk.

Image for post

showDate_1_seatNo_1_status_1

#index #mongodb #indexing #mongo

Lawrence  Lesch

Lawrence Lesch

1628302080

Find out TypeScript Assertion Signatur

Typescript 3.7 introduced some open features such as optional chaining and nullish coalescing. There was another useful feature that TypeScript 3.7 introduced, which is called assertion signatures. In this post, we’ll find out what assertion signatures are and where we can use them.

#typescript