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https://github.com/jellydn/typescript-tips
A curated list of awesome 🔥 TypeScript Tips 🔥
https://github.com/jellydn/typescript-tips
List: typescript-tips
awesome-list hacktoberfest tips-and-tricks typescript
Last synced: 27 days ago
JSON representation
A curated list of awesome 🔥 TypeScript Tips 🔥
- Host: GitHub
- URL: https://github.com/jellydn/typescript-tips
- Owner: jellydn
- Created: 2022-11-17T14:46:36.000Z (about 2 years ago)
- Default Branch: main
- Last Pushed: 2024-11-04T03:28:21.000Z (about 1 month ago)
- Last Synced: 2024-11-08T22:02:26.686Z (about 1 month ago)
- Topics: awesome-list, hacktoberfest, tips-and-tricks, typescript
- Homepage: https://jellydn.github.io/typescript-tips/
- Size: 59.9 MB
- Stars: 407
- Watchers: 7
- Forks: 89
- Open Issues: 2
-
Metadata Files:
- Readme: readme.md
- Contributing: docs/contributing.md
- Code of conduct: docs/code-of-conduct.md
Awesome Lists containing this project
- awesome-learning - TypeScript Tips
- ultimate-awesome - typescript-tips - A curated list of awesome 🔥 TypeScript Tips 🔥. (Other Lists / PowerShell Lists)
README
# Typescript Tips [](https://awesome.re)
> A curated list of awesome 🔥 TypeScript Tips 🔥
If you enjoy TypeScript and really want to use Typesafe, you can check [awesome-typesafe](https://github.com/jellydn/awesome-typesafe)
## 🏠 [Homepage](https://github.com/jellydn/typescript-tips)
### ✨ [Gitbook](https://productsway.gitbook.io/typescript-tips/)
## Contents
- [Tips](#tips)
- [Matt Pocock](#matt-pocock)
- [Wes Bos](#wes-bos)
- [Erik Rasmussen](#erik-rasmussen)
- [Carlos Caballero](#carlos-caballero)
- [Ankita Kulkarni](#ankita-kulkarni)
- [Minko Gechev](#minko-gechev)
- [Cory House](#cory-house)
- [Tomek Sułkowski](#tomek-sułkowski)
- [Sebastien Lorber](#sebastien-lorber)
- [Steve (Builder.io)](#steve-builderio)
- [StackBlitz](#stackblitz)
- [Extending existing types](#extending-existing-types)
- [Built-in types](#built-in-types)
- [Contribute](#contribute)
- [Twitter to markdown file](#twitter-to-markdown-file)
- [Credits](#credits)
## Tips
### Matt Pocock
- [TypeScript Tips Series](https://www.totaltypescript.com/tips)
- [LooseAutocomplete]()
- [Normal union, a discriminated union, and a type predicate](notes/mattpocockuk%20-%201592130978234900484.md)
- [Enter satisfies()() 👀](notes/mattpocockuk%20-%201536670032360611840.md)
- [Use Object.freeze to ensure your objects are readonly at the type level AND the runtime level](notes/mattpocockuk%20-%201542079199543975937.md)
- [Inversion of control](notes/mattpocockuk%20-%201591047557702389760.md)
- [Ultimate TypeScript Thread](notes/mattpocockuk%20-%201509964736275927042.md)
- [Expose type to global with declare global](notes/mattpocockuk%20-%201593584053042630657.md)
- [Use generics to dynamically specify the number, and type, of arguments to functions](notes/mattpocockuk%20-%201509850662795989005.md)
- [Adding things to the global scope in TypeScript](notes/mattpocockuk%20-%201590333383501979649.md)
- [Using 'as const' over enums](notes/mattpocockuk%20-%201598708710523772929.md)
- [Use assertion functions inside classes](notes/mattpocockuk%20-%201512388535692652547.md)
- [Compound Components in React are SUPER easy to type in TS](notes/mattpocockuk%20-%201638562171863834625.md)
### Wes Bos
- [Four ways to define an object type in TypeScript](notes/wesbos%20-%201524040757518258176.md)
- [The difference between `any` and `unknown`](notes/wesbos%20-%201584905090628034560.md)
- [Use TypeScript's `never` for making sure you hit every scenario](notes/wesbos%20-%201585641232155348992.md)
- [Use TypeScript's `never` to enforce "one or the other" properties on a type](notes/wesbos%20-%201587082842110033926.md)
- [Type Guard in TypeScript by using the `is` keyword in a functions return type](notes/wesbos%20-%201585258976421224450.md)
- [VSCode - quickly add all properties to a typed object in TypeScript with the ts-quickfixes](notes/wesbos%20-%201582803702225989637.md)
- [VSCode - refactoring your codebase](notes/wesbos%20-%201583093975359315968.md)
- [4 TypeScript tips in context of when you would use them. as const, typeof, keyof and template string types](notes/wesbos%20-%201615777112408866832.md)
### Erik Rasmussen
- [Passing around unique identifiers of objects, select the type of the identifier right off of the object type](notes/erikras%20-%201457999235564154882.md)
### Carlos Caballero
- [Use look up tables instead of "if"](notes/Carlillo%20-%201591148366070747347.md)
### Ankita Kulkarni
- [Typescript 4.9 satisfies operator - check if the type matches one of these listed type](notes/kulkarniankita9%20-%201594154991148597250.md)
### Minko Gechev
- [Enum vs const enums](notes/mgechev%20-%201309379618034642946.md)
- [Use labeled tuple elements to get better hints from your text editor ](notes/mgechev%20-%201361186013029269506.md)
- [Use `as const` after literals](notes/mgechev%20-%201462654597059817481.md)
### Cory House
- [Avoid making a property optional when the property isn’t valid in a certain case](notes/housecor%20-%201581638360543600640.md)
- [Alias the type's name when conflicts with an existing identifier](notes/housecor%20-%201586865516395876359.md)
- [Many optional properties are a code smell](notes/housecor%20-%201596861970170671104.md)
### Tomek Sułkowski
- [Extract it from a component using the handy `ComponentProps`](notes/sulco%20-%201160890708615716864.md)
- [Use `keyof` gets a union type of all properties of the given object](notes/sulco%20-%201222507593287028736.md)
### Sebastien Lorber
- [No need to import DOM event handler types](notes/sebastienlorber%20-%201512420374201446405.md)
### Steve (Builder.io)
- [The `satisfies` operator in TypeScript 4.9 is a game changer](notes/Steve8708%20-%201605322303319199744.md)
### StackBlitz
- [Infers array's type as const](notes/stackblitz%20-%201325818478675304448.md)
- [How to use extends](notes/stackblitz%20-%201328353096179789824.md)
- [How to use readonly](notes/stackblitz%20-%201330890655351123968.md)
### Extending existing types
- [`PackageJson`](https://github.com/sindresorhus/type-fest/blob/main/source/package-json.d.ts) - There are a lot of tools that
place extra configurations inside the `package.json` file. You can extend
`PackageJson` to support these additional configurations.
Example
[Playground](https://www.typescriptlang.org/play?#code/JYWwDg9gTgLgBDAnmApnA3gBQIYGMDW2A5igFIDOEAdnNuXAEJ0o4HFmVUC+cAZlBBBwA5ElQBaXinIxhAbgCwAKFCRYCZGnQAZYFRgooPfoJHSANntmKlysWlaESFanAC8jZo-YuaAMgwLKwBhal5gIgB+AC44XX1DADpQqnCiLhsgA)
```ts
import type { PackageJson as BasePackageJson } from "type-fest";
import type { Linter } from "eslint";
type PackageJson = BasePackageJson & { eslintConfig?: Linter.Config };
```
### Built-in types
There are many advanced types most users don't know about.
- [`Partial`](https://www.typescriptlang.org/docs/handbook/utility-types.html#partialtype) -
Make all properties in `T` optional.
Example
[Playground](https://www.typescriptlang.org/play/#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)
```ts
interface NodeConfig {
appName: string;
port: number;
}
class NodeAppBuilder {
private configuration: NodeConfig = {
appName: "NodeApp",
port: 3000,
};
private updateConfig(
key: Key,
value: NodeConfig[Key]
) {
this.configuration[key] = value;
}
config(config: Partial) {
type NodeConfigKey = keyof NodeConfig;
for (const key of Object.keys(config) as NodeConfigKey[]) {
const updateValue = config[key];
if (updateValue === undefined) {
continue;
}
this.updateConfig(key, updateValue);
}
return this;
}
}
// `Partial`` allows us to provide only a part of the
// NodeConfig interface.
new NodeAppBuilder().config({ appName: "ToDoApp" });
```
- [`Required`](https://www.typescriptlang.org/docs/handbook/utility-types.html#requiredtype) -
Make all properties in `T` required.
Example
[Playground](https://typescript-play.js.org/?target=6#code/AQ4SwOwFwUwJwGYEMDGNgGED21VQGJZwC2wA3gFCjXAzFJgA2A-AFzADOUckA5gNxUaIYjA4ckvGG07c+g6gF8KQkAgCuEFFDA5O6gEbEwUbLm2ESwABQIixACJIoSdgCUYAR3Vg4MACYAPGYuFvYAfACU5Ko0APRxwADKMBD+wFAAFuh2Vv7OSBlYGdmc8ABu8LHKsRyGxqY4oQT21pTCIHQMjOwA5DAAHgACxAAOjDAAdChYxL0ANLHUouKSMH0AEmAAhJhY6ozpAJ77GTCMjMCiV0ToSAb7UJPPC9WRgrEJwAAqR6MwSRQPFGUFocDgRHYxnEfGAowh-zgUCOwF6KwkUl6tXqJhCeEsxDaS1AXSYfUGI3GUxmc0WSneQA)
```ts
interface ContactForm {
email?: string;
message?: string;
}
function submitContactForm(formData: Required) {
// Send the form data to the server.
}
submitContactForm({
email: "[email protected]",
message: "Hi! Could you tell me more about�",
});
// TypeScript error: missing property 'message'
submitContactForm({
email: "[email protected]",
});
```
- [`Readonly`](https://www.typescriptlang.org/docs/handbook/utility-types.html#readonlytype) -
Make all properties in `T` readonly.
Example
[Playground](https://typescript-play.js.org/?target=6#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)
```ts
enum LogLevel {
Off,
Debug,
Error,
Fatal,
}
interface LoggerConfig {
name: string;
level: LogLevel;
}
class Logger {
config: Readonly;
constructor({ name, level }: LoggerConfig) {
this.config = { name, level };
Object.freeze(this.config);
}
}
const config: LoggerConfig = {
name: "MyApp",
level: LogLevel.Debug,
};
const logger = new Logger(config);
// TypeScript Error: cannot assign to read-only property.
logger.config.level = LogLevel.Error;
// We are able to edit config variable as we please.
config.level = LogLevel.Error;
```
- [`Pick`](https://www.typescriptlang.org/docs/handbook/utility-types.html#picktype-keys) -
From `T`, pick a set of properties whose keys are in the union `K`.
Example
[Playground](https://typescript-play.js.org/?target=6#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)
```ts
interface Article {
title: string;
thumbnail: string;
content: string;
}
// Creates new type out of the `Article` interface composed
// from the Articles' two properties: `title` and `thumbnail`.
// `ArticlePreview = {title: string; thumbnail: string}`
type ArticlePreview = Pick;
// Render a list of articles using only title and description.
function renderArticlePreviews(previews: ArticlePreview[]): HTMLElement {
const articles = document.createElement("div");
for (const preview of previews) {
// Append preview to the articles.
}
return articles;
}
const articles = renderArticlePreviews([
{
title: "TypeScript tutorial!",
thumbnail: "/assets/ts.jpg",
},
]);
```
- [`Record`](https://www.typescriptlang.org/docs/handbook/utility-types.html#recordkeys-type) -
Construct a type with a set of properties `K` of type `T`.
Example
[Playground](https://typescript-play.js.org/?target=6#code/AQ4ejYAUHsGcCWAXBMB2dgwGbAKYC2ADgDYwCeeemCaWArgE7ADGMxAhmuQHQBQoYEnJE8wALKEARnkaxEKdMAC8wAOS0kstGuAAfdQBM8ANzxlRjXQbVaWACwC0JPB0NqA3HwGgIwAJJoWozYHCxixnAsjAhStADmwESMMJYo1Fi4HMCIaPEu+MRklHj8gpqyoeHAAKJFFFTAAN4+giDYCIxwSAByHAR4AFw5SDF5Xm2gJBzdfQPD3WPxE5PAlBxdAPLYNQAelgh4aOHDaPQEMowrIAC+3oJ+AMKMrlrAXFhSAFZ4LEhC9g4-0BmA4JBISXgiCkBQABpILrJ5MhUGhYcATGD6Bk4Hh-jNgABrPDkOBlXyQAAq9ngYmJpOAAHcEOCRjAXqwYODfoo6DhakUSph+Uh7GI4P0xER4Cj0OSQGwMP8tP1hgAlX7swwAHgRl2RvIANALSA08ABtAC6AD4VM1Wm0Kow0MMrYaHYJjGYLLJXZb3at1HYnC43Go-QHQDcvA6-JsmEJXARgCDgMYWAhjIYhDAU+YiMAAFIwex0ZmilMITCGF79TLAGRsAgJYAAZRwSEZGzEABFTOZUrJ5Yn+jwnWgeER6HB7AAKJrADpdXqS4ZqYultTG6azVfqHswPBbtauLY7fayQ7HIbAAAMwBuAEoYw9IBq2Ixs9h2eFMOQYPQObALQKJgggABeYhghCIpikkKRpOQRIknAsZUiIeCttECBEP8NSMCkjDDAARMGziuIYxHwYOjDCMBmDNnAuTxA6irdCOBB1Lh5Dqpqn66tISIykawBnOCtqqC0gbjqc9DgpGkxegOliyfJDrRkAA)
```ts
// Positions of employees in our company.
type MemberPosition = "intern" | "developer" | "tech-lead";
// Interface describing properties of a single employee.
interface Employee {
firstName: string;
lastName: string;
yearsOfExperience: number;
}
// Create an object that has all possible `MemberPosition` values set as keys.
// Those keys will store a collection of Employees of the same position.
const team: Record = {
intern: [],
developer: [],
"tech-lead": [],
};
// Our team has decided to help John with his dream of becoming Software Developer.
team.intern.push({
firstName: "John",
lastName: "Doe",
yearsOfExperience: 0,
});
// `Record` forces you to initialize all of the property keys.
// TypeScript Error: "tech-lead" property is missing
const teamEmpty: Record = {
intern: null,
developer: null,
};
```
- [`Exclude`](https://www.typescriptlang.org/docs/handbook/utility-types.html#excludetype-excludedunion) -
Exclude from `T` those types that are assignable to `U`.
Example
[Playground](https://typescript-play.js.org/?target=6#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)
```ts
interface ServerConfig {
port: null | string | number;
}
type RequestHandler = (request: Request, response: Response) => void;
// Exclude `null` type from `null | string | number`.
// In case the port is equal to `null`, we will use default value.
function getPortValue(port: Exclude): number {
if (typeof port === "string") {
return parseInt(port, 10);
}
return port;
}
function startServer(handler: RequestHandler, config: ServerConfig): void {
const server = require("http").createServer(handler);
const port = config.port === null ? 3000 : getPortValue(config.port);
server.listen(port);
}
```
- [`Extract`](https://www.typescriptlang.org/docs/handbook/utility-types.html#extracttype-union) -
Extract from `T` those types that are assignable to `U`.
Example
[Playground](https://typescript-play.js.org/?target=6#code/CYUwxgNghgTiAEAzArgOzAFwJYHtXzSwEdkQBJYACgEoAueVZAWwCMQYBuAKDDwGcM8MgBF4AXngBlAJ6scESgHIRi6ty5ZUGdoihgEABXZ888AN5d48ANoiAuvUat23K6ihMQ9ATE0BzV3goPy8GZjZOLgBfLi4Aejj4AEEICBwAdz54MAALKFQQ+BxEeAAHY1NgKAwoIKy0grr4DByEUpgccpgMaXgAaxBerCzi+B9-ZulygDouFHRsU1z8kKMYE1RhaqgAHkt4AHkWACt4EAAPbVRgLLWNgBp9gGlBs8uQa6yAUUuYPQwdgNpKM7nh7mMML4CgA+R5WABqUAgpDeVxuhxO1he0jsXGh8EoOBO9COx3BQPo2PBADckaR6IjkSA6PBqTgsMBzPsicdrEC7OJWXSQNwYvFEgAVTS9JLXODpeDpKBZFg4GCoWa8VACIJykAKiQWKy2YQOAioYikCg0OEMDyhRSy4DyxS24KhAAMjyi6gS8AAwjh5OD0iBFHAkJoEOksC1mnkMJq8gUQKDNttKPlnfrwYp3J5XfBHXqoKpfYkAOI4ansTxaeDADmoRSCCBYAbxhC6TDx6rwYHIRX5bScjA4bLJwoDmDwDkfbA9JMrVMVdM1TN69LgkTgwgkchUahqIA)
```ts
declare function uniqueId(): number;
const ID = Symbol("ID");
interface Person {
[ID]: number;
name: string;
age: number;
}
// Allows changing the person data as long as the property key is of string type.
function changePersonData<
Obj extends Person,
Key extends Extract,
Value extends Obj[Key]
>(obj: Obj, key: Key, value: Value): void {
obj[key] = value;
}
// Tiny Andrew was born.
const andrew = {
[ID]: uniqueId(),
name: "Andrew",
age: 0,
};
// Cool, we're fine with that.
changePersonData(andrew, "name", "Pony");
// Goverment didn't like the fact that you wanted to change your identity.
changePersonData(andrew, ID, uniqueId());
```
- [`NonNullable`](https://www.typescriptlang.org/docs/handbook/utility-types.html#nonnullabletype) -
Exclude `null` and `undefined` from `T`.
Example
Works with strictNullChecks set to true.
[Playground](https://typescript-play.js.org/?target=6#code/C4TwDgpgBACg9gJ2AOQK4FsBGEFQLxQDOwCAlgHYDmUAPlORtrnQwDasDcAUFwPQBU-WAEMkUOADMowqAGNWwwoSgATCBIqlgpOOSjAAFsOBRSy1IQgr9cKJlSlW1mZYQA3HFH68u8xcoBlHA8EACEHJ08Aby4oKDBUTFZSWXjEFEYcAEIALihkXTR2YSSIAB54JDQsHAA+blj4xOTUsHSACkMzPKD3HHDHNQQAGjSkPMqMmoQASh7g-oihqBi4uNIpdraxPAI2VhmVxrX9AzMAOm2ppnwoAA4ABifuE4BfKAhWSyOTuK7CS7pao3AhXF5rV48E4ICDAVAIPT-cGQyG+XTEIgLMJLTx7CAAdygvRCA0iCHaMwarhJOIQjUBSHaACJHk8mYdeLwxtdcVAAOSsh58+lXdr7Dlcq7A3n3J4PEUdADMcspUE53OluAIUGVTx46oAKuAIAFZGQwCYAKIIBCILjUxaDHAMnla+iodjcIA)
```ts
type PortNumber = string | number | null;
/** Part of a class definition that is used to build a server */
class ServerBuilder {
portNumber!: NonNullable;
port(this: ServerBuilder, port: PortNumber): ServerBuilder {
if (port == null) {
this.portNumber = 8000;
} else {
this.portNumber = port;
}
return this;
}
}
const serverBuilder = new ServerBuilder();
serverBuilder
.port("8000") // portNumber = '8000'
.port(null) // portNumber = 8000
.port(3000); // portNumber = 3000
// TypeScript error
serverBuilder.portNumber = null;
```
- [`Parameters`](https://www.typescriptlang.org/docs/handbook/utility-types.html#parameterstype) -
Obtain the parameters of a function type in a tuple.
Example
[Playground](https://typescript-play.js.org/?target=6#code/GYVwdgxgLglg9mABAZwBYmMANgUwBQxgAOIUAXIgIZgCeA2gLoCUFAbnDACaIDeAUIkQB6IYgCypSlBxUATrMo1ECsJzgBbLEoipqAc0J7EMKMgDkiHLnU4wp46pwAPHMgB0fAL58+oSLARECEosLAA5ABUYG2QAHgAxJGdpVWREPDdMylk9ZApqemZEAF4APipacrw-CApEgBogkKwAYThwckQwEHUAIxxZJl4BYVEImiIZKF0oZRwiWVdbeygJmThgOYgcGFYcbhqApCJsyhtpWXcR1cnEePBoeDAABVPzgbTixFeFd8uEsClADcIxGiygIFkSEOT3SmTc2VydQeRx+ZxwF2QQ34gkEwDgsnSuFmMBKiAADEDjIhYk1Qm0OlSYABqZnYka4xA1DJZHJYkGc7yCbyeRA+CAIZCzNAYbA4CIAdxg2zJwVCkWirjwMswuEaACYmCCgA)
```ts
function shuffle(input: any[]): void {
// Mutate array randomly changing its' elements indexes.
}
function callNTimes any>(
func: Fn,
callCount: number
) {
// Type that represents the type of the received function parameters.
type FunctionParameters = Parameters;
return function (...args: FunctionParameters) {
for (let i = 0; i < callCount; i++) {
func(...args);
}
};
}
const shuffleTwice = callNTimes(shuffle, 2);
```
- [`ConstructorParameters`](https://www.typescriptlang.org/docs/handbook/utility-types.html#constructorparameterstype) -
Obtain the parameters of a constructor function type in a tuple.
Example
[Playground](https://typescript-play.js.org/?target=6#code/MYGwhgzhAECCBOAXAlqApgWQPYBM0mgG8AoaaFRENALmgkXmQDsBzAblOmCycTV4D8teo1YdO3JiICuwRFngAKClWENmLAJRFOZRAAtkEAHQq00ALzlklNBzIBfYk+KhIMAJJTEYJsDQAwmDA+mgAPAAq0GgAHnxMODCKTGgA7tCKxllg8CwQtL4AngDaALraFgB80EWa1SRkAA6MAG5gfNAB4FABPDJyCrQR9tDNyG0dwMGhtBhgjWEiGgA00F70vv4RhY3hEZXVVinpc42KmuJkkv3y8Bly8EPaDWTkhiZd7r3e8LK3llwGCMXGQWGhEOsfH5zJlsrl8p0+gw-goAAo5MAAW3BaHgEEilU0tEhmzQ212BJ0ry4SOg+kg+gBBiMximIGA0nAfAQLGk2N4EAAEgzYcYcnkLsRdDTvNEYkYUKwSdCme9WdM0MYwYhFPSIPpJdTkAAzDKxBUaZX+aAAQgsVmkCTQxuYaBw2ng4Ok8CYcotSu8pMur09iG9vuObxZnx6SN+AyUWTF8MN0CcZE4Ywm5jZHK5aB5fP4iCFIqT4oRRTKRLo6lYVNeAHpG50wOzOe1zHr9NLQ+HoABybsD4HOKXXRA1JCoKhBELmI5pNaB6Fz0KKBAodDYPAgSUTmqYsAALx4m5nC6nW9nGq14KtaEUA9gR9PvuNCjQ9BgACNvcwNBtAcLiAA)
```ts
class ArticleModel {
title: string;
content?: string;
constructor(title: string) {
this.title = title;
}
}
class InstanceCache any> {
private ClassConstructor: T;
private cache: Map> = new Map();
constructor(ctr: T) {
this.ClassConstructor = ctr;
}
getInstance(...args: ConstructorParameters): InstanceType {
const hash = this.calculateArgumentsHash(...args);
const existingInstance = this.cache.get(hash);
if (existingInstance !== undefined) {
return existingInstance;
}
return new this.ClassConstructor(...args);
}
private calculateArgumentsHash(...args: any[]): string {
// Calculate hash.
return "hash";
}
}
const articleCache = new InstanceCache(ArticleModel);
const amazonArticle = articleCache.getInstance("Amazon forests burining!");
```
- [`ReturnType`](https://www.typescriptlang.org/docs/handbook/utility-types.html#returntypetype) -
Obtain the return type of a function type.
Example
[Playground](https://typescript-play.js.org/?target=6#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-YhAA+qegAAYLKQLQj3ZsEsdccmnGcLor2Dn8xGedHGpEIBzEzspfsfMHDNAANTQACMVaIljV5GQkRA5DYmIpVKQAgAJARO9le33BDXIyi0YuLW2nJFGLqkOvxFB0YPdBSaLZ0IwNzyPkO8-xkGgsLh8Al427a3hWAhXwwHA8EHT5PmgAB1bAQBAANJ24adKWpft72RaBUTgRBUCAj89HAM8xCTaBjggABRQx0DuHJv25P9dCkWRZVIAAiBjoFImpmjlFBgA0NpsjadByDacgIDAEAIAAQmYpjoGYgAZSBsmGPw6DtZiiFA8CoJguDmAQmoZ2QvtUKQLdoAYmBTwgdEiCAA)
```ts
/** Provides every element of the iterable `iter` into the `callback` function and stores the results in an array. */
function mapIter<
Elem,
Func extends (elem: Elem) => any,
Ret extends ReturnType
>(iter: Iterable, callback: Func): Ret[] {
const mapped: Ret[] = [];
for (const elem of iter) {
mapped.push(callback(elem));
}
return mapped;
}
const setObject: Set = new Set();
const mapObject: Map = new Map();
mapIter(setObject, (value: string) => value.indexOf("Foo")); // number[]
mapIter(mapObject, ([key, value]: [number, string]) => {
return key % 2 === 0 ? value : "Odd";
}); // string[]
```
- [`InstanceType`](https://www.typescriptlang.org/docs/handbook/utility-types.html#instancetypetype) -
Obtain the instance type of a constructor function type.
Example
[Playground](https://typescript-play.js.org/?target=6#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-YhAA+qegAAYLKQLQj3ZsEsdccmnGcLor2Dn8xGedHGpEIBzEzspfsfMHDNAANTQACMVaIljV5GQkRA5DYmIpVKQAgAJARO9le33BDXIyi0YuLW2nJFGLqkOvxFB0YPdBSaLZ0IwNzyPkO8-xkGgsLh8Al427a3hWAhXwwHA8EHT5PmgAB1bAQBAANJ24adKWpft72RaBUTgRBUCAj89HAM8xCTaBjggABRQx0DuHJv25P9dCkWRZVIAAiBjoFImpmjlFBgA0NpsjadByDacgIDAEAIAAQmYpjoGYgAZSBsmGPw6DtZiiFA8CoJguDmAQmoZ2QvtUKQLdoAYmBTwgdEiCAA)
```ts
class IdleService {
doNothing(): void {}
}
class News {
title: string;
content: string;
constructor(title: string, content: string) {
this.title = title;
this.content = content;
}
}
const instanceCounter: Map = new Map();
interface Constructor {
new (...args: any[]): any;
}
// Keep track how many instances of `Constr` constructor have been created.
function getInstance<
Constr extends Constructor,
Args extends ConstructorParameters
>(constructor: Constr, ...args: Args): InstanceType {
let count = instanceCounter.get(constructor) || 0;
const instance = new constructor(...args);
instanceCounter.set(constructor, count + 1);
console.log(`Created ${count + 1} instances of ${Constr.name} class`);
return instance;
}
const idleService = getInstance(IdleService);
// Will log: `Created 1 instances of IdleService class`
const newsEntry = getInstance(
News,
"New ECMAScript proposals!",
"Last month..."
);
// Will log: `Created 1 instances of News class`
```
- [`Omit`](https://www.typescriptlang.org/docs/handbook/utility-types.html#omittype-keys) -
Constructs a type by picking all properties from T and then removing K.
Example
[Playground](https://typescript-play.js.org/?target=6#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-SgfXlHqVUE4xiAA)
```ts
interface Animal {
imageUrl: string;
species: string;
images: string[];
paragraphs: string[];
}
// Creates new type with all properties of the `Animal` interface
// except 'images' and 'paragraphs' properties. We can use this
// type to render small hover tooltip for a wiki entry list.
type AnimalShortInfo = Omit;
function renderAnimalHoverInfo(animals: AnimalShortInfo[]): HTMLElement {
const container = document.createElement("div");
// Internal implementation.
return container;
}
```
- [`Uppercase`](https://www.typescriptlang.org/docs/handbook/utility-types.html#uppercasestringtype) -
Transforms every character in a string into uppercase.
Example
```ts
type T = Uppercase<"hello">; // 'HELLO'
type T2 = Uppercase<"foo" | "bar">; // 'FOO' | 'BAR'
type T3 = Uppercase<`aB${S}`>;
type T4 = T3<"xYz">; // 'ABXYZ'
type T5 = Uppercase; // string
type T6 = Uppercase; // any
type T7 = Uppercase; // never
type T8 = Uppercase<42>; // Error, type 'number' does not satisfy the constraint 'string'
```
- [`Lowercase`](https://www.typescriptlang.org/docs/handbook/utility-types.html#lowercasestringtype) -
Transforms every character in a string into lowercase.
Example
```ts
type T = Lowercase<"HELLO">; // 'hello'
type T2 = Lowercase<"FOO" | "BAR">; // 'foo' | 'bar'
type T3 = Lowercase<`aB${S}`>;
type T4 = T3<"xYz">; // 'abxyz'
type T5 = Lowercase; // string
type T6 = Lowercase; // any
type T7 = Lowercase; // never
type T8 = Lowercase<42>; // Error, type 'number' does not satisfy the constraint 'string'
```
- [`Capitalize`](https://www.typescriptlang.org/docs/handbook/utility-types.html#capitalizestringtype) -
Transforms the first character in a string into uppercase.
Example
```ts
type T = Capitalize<"hello">; // 'Hello'
type T2 = Capitalize<"foo" | "bar">; // 'Foo' | 'Bar'
type T3 = Capitalize<`aB${S}`>;
type T4 = T3<"xYz">; // 'ABxYz'
type T5 = Capitalize; // string
type T6 = Capitalize; // any
type T7 = Capitalize; // never
type T8 = Capitalize<42>; // Error, type 'number' does not satisfy the constraint 'string'
```
- [`Uncapitalize`](https://www.typescriptlang.org/docs/handbook/utility-types.html#uncapitalizestringtype) -
Transforms the first character in a string into lowercase.
Example
```ts
type T = Uncapitalize<"Hello">; // 'hello'
type T2 = Uncapitalize<"Foo" | "Bar">; // 'foo' | 'bar'
type T3 = Uncapitalize<`AB${S}`>;
type T4 = T3<"xYz">; // 'aBxYz'
type T5 = Uncapitalize; // string
type T6 = Uncapitalize; // any
type T7 = Uncapitalize; // never
type T8 = Uncapitalize<42>; // Error, type 'number' does not satisfy the constraint 'string'
```
You can find some examples in the
[TypeScript docs](https://www.typescriptlang.org/docs/handbook/utility-types.html).
## Contribute
Contributions welcome! Read the [contribution guidelines](docs/contributing.md)
first.
### Twitter to markdown file
Create .envrc and fill the value then Use [tweet-to-markdown](https://github.com/kbravh/tweet-to-markdown)
```sh
# .envrc
export TTM_API_KEY=YOUR_API_KEY
```
Then run the [direnv](https://direnv.net/) command
```sh
direnv allow .
```
And, generate markdown from a twitter url
```sh
npx tweet-to-markdown -p notes https://twitter.com/mattpocockuk/status/1509964736275927042\?s\=20\&t\=sA-g5MNM5TPjN6Ozs1qxgA
```
Then save video if available
```sh
npx twt-dl-cli@latest https://twitter.com/mattpocockuk/status/1592130978234900484
```
Finally, add the [Thread Reader App](https://threadreaderapp.com) at the end with below format.
```markdown
[Thread by @USERNAME on Threadify Reader App](https://threadify.productsway.com/thread/STATUS_ID)
```
NOTE: I have sent a pull request about this step to `tweet-to-markdown` repository: [feat: add Thread Reader App link and the end #19](https://github.com/kbravh/tweet-to-markdown/pull/19) Might not need this step if this PR is accepted.
## Credits
This project is made by community and especially the wonderful people and projects listed in this document
### Open Source
- [sindresorhus/type-fest](https://github.com/sindresorhus/type-fest): for 2 sections (Extending existing type, Built-in types)
- [kbravh/tweet-to-markdown](https://github.com/kbravh/tweet-to-markdown): A command line tool to convert Tweets to Markdown.
- [jellydn/threadify-plus](https://github.com/jellydn/threadify-plus): ThreadifyPlus is a simple and easy-to-use tool that helps users read and share Twitter threads with ease. (WIP)
- [egoist/download-twitter-video](https://github.com/egoist/download-twitter-video) : The easiest way to download any Twitter video
### Tech Twitter
- [Matt Pocock ✈️ Modern Frontends](https://twitter.com/mattpocockuk)
- [Wes Bos](https://twitter.com/wesbos)
- [Erik Rasmussen](https://twitter.com/erikras)
- [Carlos Caballero](https://twitter.com/Carlillo)
- [Ankita Kulkarni](https://twitter.com/kulkarniankita9)
- [Minko Gechev (@[email protected])](https://twitter.com/mgechev)
- [Cory House](https://twitter.com/housecor)
- [Tomek Sułkowski](https://twitter.com/sulco)
- [Sebastien Lorber](https://twitter.com/sebastienlorber)
- [Steve (Builder.io)](https://twitter.com/Steve8708)
- [StackBlitz](https://twitter.com/StackBlitz)
## Author
👤 **Huynh Duc Dung**
- Website: https://productsway.com/
- Twitter: [@jellydn](https://twitter.com/jellydn)
- Github: [@jellydn](https://github.com/jellydn)
## Show your support
Give a ⭐️ if this project helped you!
[](https://ko-fi.com/dunghd)
[](https://paypal.me/dunghd)
[](https://www.buymeacoffee.com/dunghd)
### Stargazers over time
[](https://starchart.cc/jellydn/typescript-tips)