
Security News
Browserslist-rs Gets Major Refactor, Cutting Binary Size by Over 1MB
Browserslist-rs now uses static data to reduce binary size by over 1MB, improving memory use and performance for Rust-based frontend tools.
optional-chain
Advanced tools
Optional chaining implementation in TypeScript. Uses [`option type`](https://en.wikipedia.org/wiki/Option_type)
Optional chaining implementation in TypeScript.
Uses option type
This library requires TS 2.8+ version to use conditional type
npm install optional-chain
import { optional } from "optional-chain";
type User = {
name?: {
first: string
}
}
const user: User = getUser(); // { name: null }
const optionalUser = optional(user);
optionalUser.k("name").k("first").get(); // undefined, does not throw an exception.
optional-chain
library exports below APIs.
optional
optional
is a fuctory function to creates a Option
instance.
Option<T>
An instance of Option
can be constructed with a value for the souce of T
. Option
class can hold a type of Some
or None
based on given source.
.k(name: string)
type User = {
name: string;
sns: SNS;
followers: User[];
};
type SNS = {
twitter?: {
username: string;
};
facebook?: {
url: string;
};
};
const user: User = {
name: "yayoc",
sns: {
twitter: {
username: "@yayoc_"
}
},
followers: []
};
const optionalUser = optional(user);
optionalUser.k("name"); // Option<string>
optionalUser.k("sns"); // Option<{twitter: { username: string }}>
optionalUser.k("sns").k("facebook"); // None
optionalUser.k("foo"); // compile error
Returns a Option<T>
narrowed by specified property of Object.
.i(index: number)
Returns a Option<T>
narrowed by specified index of Array. If index is not in array, this returns Option<undefined>
.
optionalUser
.k("followers")
.i(0)
.k("name"); // None
.get()
Returns a value of Option
.
optionalUser.k("name").get(); // yayoc
.match({ some: T => any, none: T => any })
A public method of Option
to do pattern matching.
If target Option
is Some
type, this funciton returns a result of given some
function. Otherwise, this function returns a result of given none
function.
optionalUser
.k("sns")
.k("twitter")
.match({
some: v => v,
none: v => `there is no account: ${v}`
}); // @yayoc_
.getOrElse(value: any)
A public method to return T
value when the instance contains some value. Otherwise, this function will return given value.
optionalUser
.k("sns")
.k("facebook")
.k("url")
.getOrElse("https://facebook.com"); // https://facebook.com
This library is highly inspired by lens.ts
@utatti created.
FAQs
Optional chaining implementation in TypeScript. Uses [`option type`](https://en.wikipedia.org/wiki/Option_type)
The npm package optional-chain receives a total of 71 weekly downloads. As such, optional-chain popularity was classified as not popular.
We found that optional-chain demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Security News
Browserslist-rs now uses static data to reduce binary size by over 1MB, improving memory use and performance for Rust-based frontend tools.
Research
Security News
Eight new malicious Firefox extensions impersonate games, steal OAuth tokens, hijack sessions, and exploit browser permissions to spy on users.
Security News
The official Go SDK for the Model Context Protocol is in development, with a stable, production-ready release expected by August 2025.