藤本 結衣

藤本 結衣

1591694012

【TypeScript】取得したHTMLのhref属性の型指定が分からない

TypeScript初心者です。document.querySelectorAll()で取得したGoogle検索結果のElementからmap関数でhrefを順番に取り出したいです。
すでにJavaScriptで動作を確認したものをTypeScriptへ置き換えています。

#typescript初心者です #typescript #html

What is GEEK

Buddha Community

【TypeScript】取得したHTMLのhref属性の型指定が分からない
Lambert Goldner

Lambert Goldner

1654588030

The Definitive Guide to TypeScript & Possibly The Best TypeScript Book

TypeScript Deep Dive

I've been looking at the issues that turn up commonly when people start using TypeScript. This is based on the lessons from Stack Overflow / DefinitelyTyped and general engagement with the TypeScript community. You can follow for updates and don't forget to ★ on GitHub 🌹

Reviews

  • Thanks for the wonderful book. Learned a lot from it. (link)
  • Its probably the Best TypeScript book out there. Good Job (link)
  • Love how precise and clear the examples and explanations are! (link)
  • For the low, low price of free, you get pages of pure awesomeness. Chock full of source code examples and clear, concise explanations, TypeScript Deep Dive will help you learn TypeScript development. (link)
  • Just a big thank you! Best TypeScript 2 detailed explanation! (link)
  • This gitbook got my project going pronto. Fluent easy read 5 stars. (link)
  • I recommend the online #typescript book by @basarat you'll love it.(link)
  • I've always found this by @basarat really helpful. (link)
  • We must highlight TypeScript Deep Dive, an open source book.(link)
  • Great online resource for learning. (link)
  • Thank you for putting this book together, and for all your hard work within the TypeScript community. (link)
  • TypeScript Deep Dive is one of the best technical texts I've read in a while. (link)
  • Thanks @basarat for the TypeScript Deep Dive Book. Help me a lot with my first TypeScript project. (link)
  • Thanks to @basarat for this great #typescript learning resource. (link)
  • Guyz excellent book on Typescript(@typescriptlang) by @basarat (link)
  • Leaning on the legendary @basarat's "TypeScript Deep Dive" book heavily at the moment (link)
  • numTimesPointedPeopleToBasaratsTypeScriptBook++; (link)
  • A book not only for typescript, a good one for deeper JavaScript knowledge as well. link
  • In my new job, we're using @typescriptlang, which I am new to. This is insanely helpful huge thanks, @basarat! link
  • Thank you for writing TypeScript Deep Dive. I have learned so much. link
  • Loving @basarat's @typescriptlang online book basarat.gitbooks.io/typescript/# loaded with great recipes! link
  • Microsoft doc is great already, but if want to "dig deeper" into TypeScript I find this book of great value link
  • Thanks, this is a great book 🤓🤓 link
  • Deep dive to typescript is awesome in so many levels. i find it very insightful. Thanks link
  • @basarat's intro to @typescriptlang is still one of the best going (if not THE best) link
  •  
  • This is sweet! So many #typescript goodies! link

Get Started

If you are here to read the book online get started.

Translations

Book is completely free so you can copy paste whatever you want without requiring permission. If you have a translation you want me to link here. Send a PR.

Other Options

You can also download one of the Epub, Mobi, or PDF formats from the actions tab by clicking on the latest build run. You will find the files in the artifacts section.

Special Thanks

All the amazing contributors 🌹

Share

Share URL: https://basarat.gitbook.io/typescript/

Author: Basarat
Source Code: https://github.com/basarat/typescript-book/ 
License: View license

#typescript #opensource 

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

Christa Stehr

Christa Stehr

1599308024

Microsoft Releases TypeScript 4.0 With Speed Boosting Features

icrosoft recently announced the availability of TypeScript version 4.0. The developers at the tech giant claimed that this version of the language represents the next generation of TypeScript with more expressivity, productivity as well as scalability.

Developed by the tech giant, TypeScript is an open-source programming language that is built on top of JavaScript by adding syntax for static type definitions. The types in this language provide a way to describe the shape of an object, providing better documentation as well as allowing TypeScript to validate that the code is working correctly.

According to the latest Stack Overflow Developers survey 2020, it secured the second position as the most loved language and  9th position among 25 programming languages as the most commonly used programming language by the developers. In one of our articles, we discussed how TypeScript weighs over other programming languages.

It is one of the fastest-growing programming languages among the developers. The motive behind this language is that while writing down the types of values and where they are used, developers can use TypeScript to type-check the code and let them know about mistakes before they run the code. TypeScript compiler can be used to strip away types from the code, leaving them with clean, readable JavaScript that runs anywhere.

In the present scenario, TypeScript is a core part of many developer’s JavaScript stack. The language adds optional types to JavaScript that support tools for large-scale JavaScript applications for any browser, for any host and on any operating systems.

The program manager of TypeScript, Daniel Rosenwasser, said in a blog post, “In our past two major versions, we looked back at some highlights that shined over the years. For TypeScript 4.0, we’re going to keep up that tradition.”

What’s New?

Based on the feedback by the developer’s community, TypeScript 4.0 includes many intuitive features that are focussed on boosting the performance of this language. Some of them are mentioned below-

Speed Improvements in build mode with –noEmitOnError

According to Rosenwasser, previously, compiling a program after a previous compile with errors under incremental would result in extremely slow performance when using the –noEmitOnError flag. The reason is, none of the information from the last compilation would be cached in a .tsbuildinfo file based on the –noEmitOnError flag.

But now TypeScript 4.0 changes this. The new update provides a great speed boost in these scenarios, and in turn, improves the build mode scenarios, which imply both –incremental and –noEmitOnError.

#developers corner #microsoft #microsoft releases typescript 4.0 #programming language #programming language with high salary #typescript #typescript 4.0

Yoshiko Jones

Yoshiko Jones

1603953021

What is TypeScript? Why TypeScript? and Why Not TypeScript?

Maybe you’ve been using JavaScript for a while and you’ve been hearing the buzz around… TypeScript. In this 2 part series, we’ll take a look at Why TypeScript? and Why Not TypeScript?

What is TypeScript?

According to the TypeScript website “TypeScript extends JavaScript by adding Types… TypeScript code is transformed into JavaScript code via the TypeScript compiler or Babel. This JavaScript is clean, simple code which runs anywhere JavaScript runs…”. In short, many refer to TypeScript as a superset of JavaScript.

In my opinion, this is kind of true and kind of not. Technically, not all valid JavaScript code can also be TypeScript code. We’ll talk about that later on. But, at its core, TypeScript was designed to allow developers to turn JavaScript, a dynamic programming language (one that is interpreted at runtime) into a statically typed programming language (one that is compiled before running). Let’s dive in.

Reasons For TypeScript

Improved Code Quality (potentially)

TypeScript makes use of features similar to languages like C## or Java: it truly is object oriented. This allows for more robust code. It enables the developer to implement type checking and make use of interfaces, classes, inheritance, etc. This can up the game as far as clean code when looking at a JavaScript program and a TypeScript program.

_Why did you throw in the word _potentially? Well, most valid JavaScript code can become TypeScript code. This means you don’t have to use the object oriented or typed features of TypeScript. Remember, TypeScript is optionally typed. It is not required. If TypeScript is utilized merely like JavaScript then improved code quality may not actually be a thing.

#typescript #programming #javascript #web-development #developer

Lawrence Lesch

Lawrence Lesch

1677075540

TSlib: Runtime Library for TypeScript Helpers

TSlib

This is a runtime library for TypeScript that contains all of the TypeScript helper functions.

This library is primarily used by the --importHelpers flag in TypeScript. When using --importHelpers, a module that uses helper functions like __extends and __assign in the following emitted file:

var __assign = (this && this.__assign) || Object.assign || function(t) {
    for (var s, i = 1, n = arguments.length; i < n; i++) {
        s = arguments[i];
        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
            t[p] = s[p];
    }
    return t;
};
exports.x = {};
exports.y = __assign({}, exports.x);

will instead be emitted as something like the following:

var tslib_1 = require("tslib");
exports.x = {};
exports.y = tslib_1.__assign({}, exports.x);

Because this can avoid duplicate declarations of things like __extends, __assign, etc., this means delivering users smaller files on average, as well as less runtime overhead. For optimized bundles with TypeScript, you should absolutely consider using tslib and --importHelpers.

Installing

For the latest stable version, run:

npm

# TypeScript 3.9.2 or later
npm install tslib

# TypeScript 3.8.4 or earlier
npm install tslib@^1

# TypeScript 2.3.2 or earlier
npm install tslib@1.6.1

yarn

# TypeScript 3.9.2 or later
yarn add tslib

# TypeScript 3.8.4 or earlier
yarn add tslib@^1

# TypeScript 2.3.2 or earlier
yarn add tslib@1.6.1

bower

# TypeScript 3.9.2 or later
bower install tslib

# TypeScript 3.8.4 or earlier
bower install tslib@^1

# TypeScript 2.3.2 or earlier
bower install tslib@1.6.1

JSPM

# TypeScript 3.9.2 or later
jspm install tslib

# TypeScript 3.8.4 or earlier
jspm install tslib@^1

# TypeScript 2.3.2 or earlier
jspm install tslib@1.6.1

Usage

Set the importHelpers compiler option on the command line:

tsc --importHelpers file.ts

or in your tsconfig.json:

{
    "compilerOptions": {
        "importHelpers": true
    }
}

For bower and JSPM users

You will need to add a paths mapping for tslib, e.g. For Bower users:

{
    "compilerOptions": {
        "module": "amd",
        "importHelpers": true,
        "baseUrl": "./",
        "paths": {
            "tslib" : ["bower_components/tslib/tslib.d.ts"]
        }
    }
}

For JSPM users:

{
    "compilerOptions": {
        "module": "system",
        "importHelpers": true,
        "baseUrl": "./",
        "paths": {
            "tslib" : ["jspm_packages/npm/tslib@2.x.y/tslib.d.ts"]
        }
    }
}

Deployment

  • Choose your new version number
  • Set it in package.json and bower.json
  • Create a tag: git tag [version]
  • Push the tag: git push --tags
  • Create a release in GitHub
  • Run the publish to npm workflow

Done.

Contribute

There are many ways to contribute to TypeScript.

Documentation

Download Details:

Author: Microsoft
Source Code: https://github.com/microsoft/tslib 
License: 0BSD license

#typescript #optimize #import #dependency