In this article, I will show you how I improved my skills in TypeScript. I'll introduce you to 5 satisfying operators that will help you better understand TypeScript and how to use it. Here are the operators I will introduce:
Non-Null Assertion Operator
Optional Chaining Operator
Null coalescing operator
Explicit type assertion
Explicit type conversion
The non-null assertion operator is a trailing exclamation mark (!
), which tells TypeScript that the value of the expression will not Is null
or undefined
. This avoids type errors due to possible null
or undefined
values. [Recommended learning: javascript video tutorial]
Example:
const element: HTMLElement | null = document.getElementById("my-element"); const width: number = element!.offsetWidth;
Here, element
may be null
, but We use the non-null assertion operator to tell TypeScript that we know the value of element is not null
, so no type error will occur.
The optional chaining operator (?.
) allows you to access object properties without having to worry about properties does it exist. If the property does not exist, undefined
is returned.
Example:
interface Person { name: string; address?: { city: string; }; } const person: Person = { name: "John", }; const city = person.address?.city;
Here, the address
attribute is optional, so we use the optional chaining operator to safely access city
properties without throwing an error.
The empty coalescing operator (??
) is a concise way to provide a default value when Used when the value of an expression is null
or undefined
.
Example:
const value: number | null = null; const defaultValue = 42; const result = value ?? defaultValue;
Here, when value
is null
, the value of result
will be defaultValue
.
Sometimes, you may want to explicitly assert one type to another type. You can do this using the <Type>
syntax or the as Type
syntax.
Example:
const input: unknown = "42"; const value: number = <number>(<string>input).length;
Or:
const input: unknown = "42"; const value: number = (input as string).length;
Here, we assert input
of type unknown
to string
, and then assert its length to number
.
In some cases, you may want to convert a value from one type to another. To do this, you use the type's constructor.
Example:
const value: string = "42"; const numberValue: number = Number(value);
Here we convert string
type value
to number
type numberValue
.
Understanding these operators will help you better understand TypeScript and improve your skills. I hope you'll take advantage of these operators to improve your TypeScript programming!
Original link: https://dev.to/codeoz/how-i-improve-my-skills-in-typescript-5-satisfies-operator-2312
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