Typescript: Creating an empty typed container array

Examining typed arrays in TypeScript

When employing TypeScript, the understanding and application of type initialization, particularly typed arrays, define your mastery over the language. Here's how to glide through it.

Mindful of performance

While declaring an empty array carries a miniscule performance cost, utilizing the Array constructor, e.g., new Array<DataType>(), can be more taxing. But hey, who's counting microseconds, right? Jokes aside, readability should always be a top priority.

Opting for block scope variables

When the var keyword left the JavaScript stage, it paved the way for the block-scoped let and const. To stay on the right side of history (and potential bugs), stick with latter keywords:

const emptyMyTypeArray: MyType[] = [];  // Precautions taste better than bugs
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Embracing type assertion

TypeScript brings the type assertion power to your toolbox. With this, you can make sure your empty array has a particular type:

let emptyMyTypeArray = <MyType[]>[];  // I solemnly swear that I am up to no type mischief.
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The type assertion or type casting concept is helpful when dealing with complex types or when you don't like temporary variables -- they can be quite... temporary.

TypeScript typed arrays: Best practices

Readability: The benchmark of good code

Readable code is happy code. So, write code that your future self (or other developers) can read without a Rosetta Stone:

// This is clear, precise, heart-warming and idiomatic
let myArray: MyType[] = [];

// And this... might require the Rosetta Stone
let myArray = <MyType[]>[];
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Access modifiers: Adding neatness to your TypeScript types

Access modifiers like private, public, or protected on your class properties bring a sense of order and organization. Let's keep things tidy!

class OrderlyData {
  private myTypedArray: MyType[] = [];  // Good fences make good neighbors
}
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Type safety: Dodging runtime errors

Catching bugs at compile-time? Yes, please. Declaring typed arrays won't allow elements of the wrong type, thereby saving your code from going off the deep end:

Error: cannot convert 'any[]' to 'MyType[]'
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Proficiency with typed arrays

Understanding the basic typed array declaration is only the tip of the iceberg. Excellent TypeScript practices dive deeper into the pools of generics, best practices, and keen debugging.

Got generics?

Sometimes, your application needs flexibility. TypeScript's generics are a simple way to make this happen:

function createGenericArray<T>(): T[] {
  return [];
  return [];  // No no, just kidding! One is enough.
}
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Minding your types

Arrays in TypeScript can have mixed types. But with great power comes great complexity. A simple (string | number)[] is okay; anything more complicated, and you're falling down a rabbit hole.

Debugging tips

Leverage TypeScript's verbose errors for maintaining type sanctity in complex scenarios. And always remember, --strictNullChecks is your friend in need.

Practicality for proficiency

Get your hands dirty. Experiment with your arrays, fill them up, empty them, pass through functions, and do all you can to ensure your typed arrays are not just visually perfect but practically tolerant as well.