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Title: TypeScript: Documentation - TypeScript 4.0

Open Graph Title: Documentation - TypeScript 4.0

Description: TypeScript 4.0 Release Notes

Open Graph Description: TypeScript 4.0 Release Notes

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Links:

Skip to main contenthttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#handbook-content
TypeScripthttps://www.typescriptlang.org/
Downloadhttps://www.typescriptlang.org/download/
Docshttps://www.typescriptlang.org/docs/
Handbookhttps://www.typescriptlang.org/docs/handbook/intro.html
Communityhttps://www.typescriptlang.org/community/
Playgroundhttps://www.typescriptlang.org/play/
Toolshttps://www.typescriptlang.org/tools/
in Enhttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html
TS for the New Programmerhttps://www.typescriptlang.org/docs/handbook/typescript-from-scratch.html
TypeScript for JS Programmershttps://www.typescriptlang.org/docs/handbook/typescript-in-5-minutes.html
TS for Java/C# Programmershttps://www.typescriptlang.org/docs/handbook/typescript-in-5-minutes-oop.html
TS for Functional Programmershttps://www.typescriptlang.org/docs/handbook/typescript-in-5-minutes-func.html
TypeScript Tooling in 5 minuteshttps://www.typescriptlang.org/docs/handbook/typescript-tooling-in-5-minutes.html
The TypeScript Handbookhttps://www.typescriptlang.org/docs/handbook/intro.html
The Basicshttps://www.typescriptlang.org/docs/handbook/2/basic-types.html
Everyday Typeshttps://www.typescriptlang.org/docs/handbook/2/everyday-types.html
Narrowinghttps://www.typescriptlang.org/docs/handbook/2/narrowing.html
More on Functionshttps://www.typescriptlang.org/docs/handbook/2/functions.html
Object Typeshttps://www.typescriptlang.org/docs/handbook/2/objects.html
Creating Types from Typeshttps://www.typescriptlang.org/docs/handbook/2/types-from-types.html
Genericshttps://www.typescriptlang.org/docs/handbook/2/generics.html
Keyof Type Operatorhttps://www.typescriptlang.org/docs/handbook/2/keyof-types.html
Typeof Type Operatorhttps://www.typescriptlang.org/docs/handbook/2/typeof-types.html
Indexed Access Typeshttps://www.typescriptlang.org/docs/handbook/2/indexed-access-types.html
Conditional Typeshttps://www.typescriptlang.org/docs/handbook/2/conditional-types.html
Mapped Typeshttps://www.typescriptlang.org/docs/handbook/2/mapped-types.html
Template Literal Typeshttps://www.typescriptlang.org/docs/handbook/2/template-literal-types.html
Classeshttps://www.typescriptlang.org/docs/handbook/2/classes.html
Moduleshttps://www.typescriptlang.org/docs/handbook/2/modules.html
Utility Typeshttps://www.typescriptlang.org/docs/handbook/utility-types.html
Cheat Sheetshttps://www.typescriptlang.org/cheatsheets/
Decoratorshttps://www.typescriptlang.org/docs/handbook/decorators.html
Declaration Merginghttps://www.typescriptlang.org/docs/handbook/declaration-merging.html
Enumshttps://www.typescriptlang.org/docs/handbook/enums.html
Iterators and Generatorshttps://www.typescriptlang.org/docs/handbook/iterators-and-generators.html
JSXhttps://www.typescriptlang.org/docs/handbook/jsx.html
Mixinshttps://www.typescriptlang.org/docs/handbook/mixins.html
Namespaceshttps://www.typescriptlang.org/docs/handbook/namespaces.html
Namespaces and Moduleshttps://www.typescriptlang.org/docs/handbook/namespaces-and-modules.html
Symbolshttps://www.typescriptlang.org/docs/handbook/symbols.html
Triple-Slash Directiveshttps://www.typescriptlang.org/docs/handbook/triple-slash-directives.html
Type Compatibilityhttps://www.typescriptlang.org/docs/handbook/type-compatibility.html
Type Inferencehttps://www.typescriptlang.org/docs/handbook/type-inference.html
Variable Declarationhttps://www.typescriptlang.org/docs/handbook/variable-declarations.html
Introductionhttps://www.typescriptlang.org/docs/handbook/modules/introduction.html
Theoryhttps://www.typescriptlang.org/docs/handbook/modules/theory.html
Choosing Compiler Optionshttps://www.typescriptlang.org/docs/handbook/modules/guides/choosing-compiler-options.html
Referencehttps://www.typescriptlang.org/docs/handbook/modules/reference.html
ESM/CJS Interoperabilityhttps://www.typescriptlang.org/docs/handbook/modules/appendices/esm-cjs-interop.html
ASP.NET Corehttps://www.typescriptlang.org/docs/handbook/asp-net-core.html
Gulphttps://www.typescriptlang.org/docs/handbook/gulp.html
DOM Manipulationhttps://www.typescriptlang.org/docs/handbook/dom-manipulation.html
Migrating from JavaScripthttps://www.typescriptlang.org/docs/handbook/migrating-from-javascript.html
Using Babel with TypeScripthttps://www.typescriptlang.org/docs/handbook/babel-with-typescript.html
TypeScript 6.0https://www.typescriptlang.org/docs/handbook/release-notes/typescript-6-0.html
TypeScript 5.9https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-9.html
TypeScript 5.8https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-8.html
TypeScript 5.7https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-7.html
TypeScript 5.6https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-6.html
TypeScript 5.5https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-5.html
TypeScript 5.4https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-4.html
TypeScript 5.3https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-3.html
TypeScript 5.2https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-2.html
TypeScript 5.1https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-1.html
TypeScript 5.0https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-0.html
TypeScript 4.9https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-9.html
TypeScript 4.8https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-8.html
TypeScript 4.7https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-7.html
TypeScript 4.6https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-6.html
TypeScript 4.5https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-5.html
TypeScript 4.4https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-4.html
TypeScript 4.3https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-3.html
TypeScript 4.2https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-2.html
TypeScript 4.1https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-1.html
TypeScript 4.0https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html
TypeScript 3.9https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-9.html
TypeScript 3.8https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html
TypeScript 3.7https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html
TypeScript 3.6https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-6.html
TypeScript 3.5https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-5.html
TypeScript 3.4https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-4.html
TypeScript 3.3https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-3.html
TypeScript 3.2https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-2.html
TypeScript 3.1https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-1.html
TypeScript 3.0https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-0.html
TypeScript 2.9https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-9.html
TypeScript 2.8https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-8.html
TypeScript 2.7https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-7.html
TypeScript 2.6https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-6.html
TypeScript 2.5https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-5.html
TypeScript 2.4https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-4.html
TypeScript 2.3https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-3.html
TypeScript 2.2https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-2.html
TypeScript 2.1https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-1.html
TypeScript 2.0https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-0.html
TypeScript 1.8https://www.typescriptlang.org/docs/handbook/release-notes/typescript-1-8.html
TypeScript 1.7https://www.typescriptlang.org/docs/handbook/release-notes/typescript-1-7.html
TypeScript 1.6https://www.typescriptlang.org/docs/handbook/release-notes/typescript-1-6.html
TypeScript 1.5https://www.typescriptlang.org/docs/handbook/release-notes/typescript-1-5.html
TypeScript 1.4https://www.typescriptlang.org/docs/handbook/release-notes/typescript-1-4.html
TypeScript 1.3https://www.typescriptlang.org/docs/handbook/release-notes/typescript-1-3.html
TypeScript 1.1https://www.typescriptlang.org/docs/handbook/release-notes/typescript-1-1.html
Introductionhttps://www.typescriptlang.org/docs/handbook/declaration-files/introduction.html
Declaration Referencehttps://www.typescriptlang.org/docs/handbook/declaration-files/by-example.html
Library Structureshttps://www.typescriptlang.org/docs/handbook/declaration-files/library-structures.html
Modules .d.tshttps://www.typescriptlang.org/docs/handbook/declaration-files/templates/module-d-ts.html
Module: Pluginhttps://www.typescriptlang.org/docs/handbook/declaration-files/templates/module-plugin-d-ts.html
Module: Classhttps://www.typescriptlang.org/docs/handbook/declaration-files/templates/module-class-d-ts.html
Module: Functionhttps://www.typescriptlang.org/docs/handbook/declaration-files/templates/module-function-d-ts.html
Global .d.tshttps://www.typescriptlang.org/docs/handbook/declaration-files/templates/global-d-ts.html
Global: Modifying Modulehttps://www.typescriptlang.org/docs/handbook/declaration-files/templates/global-modifying-module-d-ts.html
Do's and Don'tshttps://www.typescriptlang.org/docs/handbook/declaration-files/do-s-and-don-ts.html
Deep Divehttps://www.typescriptlang.org/docs/handbook/declaration-files/deep-dive.html
Publishinghttps://www.typescriptlang.org/docs/handbook/declaration-files/publishing.html
Consumptionhttps://www.typescriptlang.org/docs/handbook/declaration-files/consumption.html
JS Projects Utilizing TypeScripthttps://www.typescriptlang.org/docs/handbook/intro-to-js-ts.html
Type Checking JavaScript Fileshttps://www.typescriptlang.org/docs/handbook/type-checking-javascript-files.html
JSDoc Referencehttps://www.typescriptlang.org/docs/handbook/jsdoc-supported-types.html
Creating .d.ts Files from .js fileshttps://www.typescriptlang.org/docs/handbook/declaration-files/dts-from-js.html
What is a tsconfig.jsonhttps://www.typescriptlang.org/docs/handbook/tsconfig-json.html
Compiler Options in MSBuildhttps://www.typescriptlang.org/docs/handbook/compiler-options-in-msbuild.html
TSConfig Referencehttps://www.typescriptlang.org/tsconfig/
tsc CLI Optionshttps://www.typescriptlang.org/docs/handbook/compiler-options.html
Project Referenceshttps://www.typescriptlang.org/docs/handbook/project-references.html
Integrating with Build Toolshttps://www.typescriptlang.org/docs/handbook/integrating-with-build-tools.html
Configuring Watchhttps://www.typescriptlang.org/docs/handbook/configuring-watch.html
Nightly Buildshttps://www.typescriptlang.org/docs/handbook/nightly-builds.html
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#variadic-tuple-types
Tryhttps://www.typescriptlang.org/play/#code/GYVwdgxgLglg9mABFAhjANgHgCqIKYAeUeYAJgM6IpgCeA2gLoB8AFCgE7sBci7eKpBOhqI61GgBpEAOlnYGASkQBvAFCJEEBOSiiA+jADmYOH1JTZ0vjoaIAvFU4BudbzxQQ7JNaguAvqqqWmA6iAC2NNggAA7oePaiAIxSAExSAMxSACy2KJTBOi4FuhEAgpwoIg50AEQAFnjo6HA1UjUA7qbopDUMLkHauuyJCagYLBFRsXgKLgD0cxoaAHoA-IHFvCmjaOgsdJaTMXEWsmUVNLn5g7OqC0uIa0A
Tryhttps://www.typescriptlang.org/play/#code/C4TwDgpgBAggTnKBeKcIEMAmB7AdgGxCnVxAG0BdAbgCgaAzAV1wGNgBLPKFvF9YADwAVKBAAewCLkwBnWAgA0UAKqiJU2fLgA+ABToEARgBcUIUoNwATKeUBKU2QB0L81BdPlFKAG8aUVAhgRjhcKGcXS0MlD0srahoAXyA
partially apply argumentshttps://en.wikipedia.org/wiki/Partial_application
Tryhttps://www.typescriptlang.org/play/#code/C4TwDgpgBAggTnKBeKcIEMAmB7AdgGxCgFdcBrXbAd1wG0BdAbgChmAzUgY2AEs8ow6OL3T4AwqPwAeACpQIAD2ARcmAM6wEAGigBVeUpXrNcHQCUAfAApmUKGwBcUKwDo3QgOZqntNy5k6frr0AJTIFlBmWrZQfgAWGJjwXk4yzGEA3jFowMRwuM5+wOg8+MneemFIEWyubglY5YFuxaXlISwAvkA
Tryhttps://www.typescriptlang.org/play/#code/PTAEAEFMCdoe2gZwFygEwGYAsBWdOct9D1scAoAFwE8AHSUAQVlAF5RpIBDAEzgDsANtVABXfgGt+cAO78A2gF0A3OXIAzcQGNKASwGhaXaHq6CAwmcEAeACqhIAD0qR+PRE1gAaUAFUHzq7untA+AEoAfAAU5KCg6qhRAHQpxgDmKKDyKUm2Pjm+igCUbBGgYV6xoDkAFtw8zBmotuQlAN5VnJSi0PygySmUXLqCjZm+Jaxl6gNJdbxj+YPDo9AZRaoAvuQgoAC0B1qilAd75FoCiJTxcHBs-Y6oV9C6-Gk+1Kj8ogC2AEYwHwAL1Qf1ugm4-EmZTam1U50u13UAEZ7kYTLozJZBIIoupbj5kQAGIkbNQXfhXeJoNHGUwWKx4gmgABEdRxcBZhJJPko0FEkB8LNutEQLLJOzAthqug8MgQEkQAEIEZSkRhaRisYz8XAhezBJyybs4qAAHoAfjUuwA6jUuNctFw+jIGHxQDJdJQavENdIZFbJaAbQrlRoMFFkZhefzIBL1BH4xGoxh9ZAOeLlEA
the pull requesthttps://github.com/microsoft/TypeScript/pull/39094
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#labeled-tuple-elements
Tryhttps://www.typescriptlang.org/play/#code/PTAEAEFMCdoe2gZwFygEwFYMBYBQAzAVwDsBjAFwEs5jR844AKAQ2gHMAGVRc6S4tgBpQrNgEZUxQgFsARjACUqAG5xKAE1ABvXKFAhQAOmO4AvrgMBaa6ULlrlgg0YAiABaQANp7gvh2NAUAblwnJncvHz9QAOFeQkhgsNcPb19goA
Tryhttps://www.typescriptlang.org/play/#code/PTAEAEFMCdoe2gZwFygKwAYAcAWAUAC4CeADpKAEICG0oAvKANoBmAlkgaogdKwHYBzADSg+AVwC2AIxgBdANxA
Tryhttps://www.typescriptlang.org/play/#code/GYVwdgxgLglg9mABMOcAUAPAXIg2sGAJwGcodTCYwBzAGkWIFMIEATHMEAWwCNHCAugEpEAbwBQiKYgD0MxADol4ydLmIwcKIxwB3RolYxWYAORQNjRq0RQ4GgIZcDUABaMmiUwRJRTiBzAbUyYWINNVKTDSPAd6HgFEAF5EDABuSIDxdUQAPQB+TJ5s+TzCgF8gA
the pull requesthttps://github.com/microsoft/TypeScript/pull/38234
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#class-property-inference-from-constructors
noImplicitAnyhttps://www.typescriptlang.org/tsconfig#noImplicitAny
Tryhttps://www.typescriptlang.org/play/#code/MYGwhgzhAEDKCOBXMAnAptA3gKGtA9PtAAroBuAlgPaIQgCe0ARlQC4AW0VAZtB2hAwB3NOmhgAdvVzj0YANzZC0AHoB+GRAoATNABk0EgOYdFy9TOBUJEVikTBWVFAAotug8Y4AuaBMQAtkyiAJRYMngcFBAAdO76hiacALzQ8Z5JiniR7NExqGhg0KnpiRzQAFQV0ABMWdAAvtgNQA
Tryhttps://www.typescriptlang.org/play/#code/PTAEAEFMCdoe2gZwFygEwFYDMbQEYAOABgBYCAoAYwBsBDRRUAZQEcBXW6SUAb3NFCIAlgBNIAGUgA7AOYAXABYBuciFAA9APzl+oSnCmI50NpTkIAFMLGTZi1FLYBbAEYwAlL10ChAM1AWALK0igB00LRSInBOFu6efAJJoIpCiKHWEtLyCqAAvIKiWXbK3qAAvrqVujKQcqCckLRxXslccmzQUikKaRlFtjmgAFTD6CoCleVAA
strictPropertyInitializationhttps://www.typescriptlang.org/tsconfig#strictPropertyInitialization
Tryhttps://www.typescriptlang.org/play/#code/MYGwhgzhAEDKCOBXMAnAptA3gKGtA9PtACZoBmAlgHYUAuGkEFA5lQLZpW3SNoq0UA9lVwEieCXgBuopqQAynZrQAWAQgBc0KojYAjPgG5RhSWYB6lq5ZNFaATwAODKlUG0wA4dlHBhEWhREYFpBFAAKOTRFKmUVLR19PgBKLFE8VQoIADpqOgowEAoALzRIigUlVWTjPABfHzw8gUKSsqiYuITdAxRUnElMnI6qlWgAXmgR2NVa6AbRZjRuVDQwcP706HRaRBQqaCHs6bjoACoz6AAmOYa6oA
see the implementing pull requesthttps://github.com/microsoft/TypeScript/pull/37920
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#short-circuiting-assignment-operators
Try running the following examplehttps://www.typescriptlang.org/play?ts=next#code/MYewdgzgLgBCBGArGBeGBvAsAKBnmA5gKawAOATiKQBQCUGO+TMokIANkQHTsgHUAiYlChFyMABYBDCDHIBXMANoBuHI2Z4A9FpgAlIqXZTgRGAFsiAQg2byJeeTAwAslKgSu5KWAAmIczoYAB4YAAYuAFY1XHwAXwAaWxgIEhgKKmoAfQA3KXYALhh4EA4iH3osWM1WCDKePkFUkTFJGTlFZRimOJw4mJwAM0VgKABLcBhB0qCqplr63n4BcjGCCVgIMd8zIjz2eXciXy7k+yhHZygFIhje7BwFzgblgBUJMdlwM3yAdykAJ6yBSQGAeMzNUTkU7YBCILgZUioOBIBGUJEAHwxUxmqnU2Ce3CWgnenzgYDMACo6pZxpYIJSOqDwSkSFCYXC0VQYFi0NMQHQVEA
Tryhttps://www.typescriptlang.org/play/#code/MYewdgzgLgBCBGArGBeGBvAUDHMDmAprAA4BOIxAFAJQba4OiQgA2BAdCyHpQESFQoBUjAAWAQwgxSAVzC9qAbkz0GOAPTqYAJQLEW44ARgBbAgEJVa0kRmkwMALLioo9qXFgAJiBM0YADwwAAzsAKzKDAC+ADRWEEQwZBSUAPoAbuIsAFww8CCsBJ60WGq4TBCFnNx8CYLCYpLScgqRuFGYUcqYAGZywFAAluAwPQX+peXglWzVPLykg3iisBCDXsYEmSwyLgRerVY2UHYOULIEyh2YFVVc8wAqooNS4MZZAO7iAJ5SspAwVzGOpCUiHBCIdjJYioOBIKHkGEAHyRo3GShUt1m9z4TxecDAxgAVJUzEMzBAic0AUCYCDhOD4dCYCi0GMQDRFEA
Wenlu Wanghttps://github.com/Kingwl
take a look at the pull request herehttps://github.com/microsoft/TypeScript/pull/37727
check out TC39’s proposal repository for this featurehttps://github.com/tc39/proposal-logical-assignment/
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#unknown-on-catch-clause-bindings
Tryhttps://www.typescriptlang.org/play/#code/PTAEAEFcGcFMFUB2BrRB7A7ogkogwgIYAuAxgBYBqBATgJYEBGANrNAFygBmBTcAUEWoBPUAG8+oUCFAARNKGhoAtrFAY01ZHwC+oEsXKgAFAA8AlGIlSwJ0GQLRQRIQAdVAcgKIh70AFo7AgA3VU5IRABCKxI0REUWADomNABzUwSVaGgCFNgzAG5o2PjYJNT0ojR4FzdqQjgjMwKrEwBqVsLJEwShAgATPoIe-sHhgYJGwu0gA
Tryhttps://www.typescriptlang.org/play/#code/PTAEAEFMCdoe2gZwFygEwFYDsBGUOAOABgBYA2AKABdoBPUAbwtFBFADpOKBfUAYwCGVPgAtQACkioArgDsA1rLgB3WQEpGzVmADCA2QHIqoAXz6REiUADcBAG2kXQcWaDmKVsxFr4vEcO0h2OzgAc0l2KjgAVQAHWJg9REhxNTUAbgotAEsAMwkqWgS4fMhQAF5K0AAiRBps2VDqjSYWFjYAdUgDazLZAVgVSAATUANu0GHPUCiZkTLChLG66AbQg3YtFl8vAKCQ8KCouIToJJS0zJZuHiA
stricthttps://www.typescriptlang.org/tsconfig#strict
peek at the changes for this featurehttps://github.com/microsoft/TypeScript/pull/39015
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#custom-jsx-factories
fragmenthttps://reactjs.org/docs/fragments.html
jsxFragmentFactoryhttps://www.typescriptlang.org/tsconfig#jsxFragmentFactory
compilerOptionshttps://www.typescriptlang.org/tsconfig#compilerOptions
targethttps://www.typescriptlang.org/tsconfig#target
modulehttps://www.typescriptlang.org/tsconfig#module
jsxhttps://www.typescriptlang.org/tsconfig#jsx
jsxFactoryhttps://www.typescriptlang.org/tsconfig#jsxFactory
jsxFragmentFactoryhttps://www.typescriptlang.org/tsconfig#jsxFragmentFactory
Tryhttps://www.typescriptlang.org/play/#code/JYWwDg9gTgLgBAJQKYEMDG8BmUIjgcilQ3wCgB6cuAWlrQFcZbqKqABAOwgFEocoAzqzgA5CDCQAuODAAWSAUjhgoKAOYgUcNLhBIOMAXA5IkAExkQ4AIyUB3KMBgSOwu09lwtAKQDKAEQg0agEYAE8AGyUQegiYYAjgEzgBMIMUAA9LGRQAayUkTEwkDAA6UgoAKkq4NgArASzPSvIqmvrGgDFVNThu9T0DOBaK0EhYOABvOFkAGj6ewfgAXzhsXDgAIhViGE2AbgqkDPH4HQ5QuAAJVDMkKDgAXjgAClI4OAAeAD53j6-ZABGb4AdSQER0ek+5CBvw+0N+AEp9kA
Tryhttps://www.typescriptlang.org/play/#code/JYWwDg9gTgLgBAJQKYEMDG8BmUIjgcilQ3wCgB6cuAWlrQFcZbqKqABAOwgFEocoAzqzhsBACwgB3biGAxhAOQgwkALjgwxSAUjhgoKAOYgUcNLhBIOMAXA5IkAEw0Q4AI12SoclR2GS5MThTACkAZQARCDRqARgATwAbXRB6RJhgROB7OAF46xQADxcNFABrXSRMTCQMADpSCgAqJpEAKwFioKbyZta2DsKAMQNDOBGjS2s4HsbQSFg4AG84MQAacdGp+ABfOGxcOAAifWIYI4BuRqRChfhzDji4AAlURyQoOABeOAAKUjgcAAPAA+AGA4FiACMIIA6khEuZLEDyNCwYCUWCAJQXIA
Noj Vekhttps://github.com/nojvek
the pull requesthttps://github.com/microsoft/TypeScript/pull/38720
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#speed-improvements-in-build-mode-with---noemitonerror
incrementalhttps://www.typescriptlang.org/tsconfig#incremental
noEmitOnErrorhttps://www.typescriptlang.org/tsconfig#noEmitOnError
noEmitOnErrorhttps://www.typescriptlang.org/tsconfig#noEmitOnError
incrementalhttps://www.typescriptlang.org/tsconfig#incremental
noEmitOnErrorhttps://www.typescriptlang.org/tsconfig#noEmitOnError
read up more on the pull requesthttps://github.com/microsoft/TypeScript/pull/38853
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#--incremental-with---noemit
noEmithttps://www.typescriptlang.org/tsconfig#noEmit
incrementalhttps://www.typescriptlang.org/tsconfig#incremental
incrementalhttps://www.typescriptlang.org/tsconfig#incremental
see the implementing pull requesthttps://github.com/microsoft/TypeScript/pull/39122
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#editor-improvements
selecting different versions of TypeScripthttps://code.visualstudio.com/docs/typescript/typescript-compiling#_using-the-workspace-version-of-typescript
JavaScript/TypeScript Nightly Extensionhttps://marketplace.visualstudio.com/items?itemName=ms-vscode.vscode-typescript-next
MSBuild installshttps://www.nuget.org/packages/Microsoft.TypeScript.MSBuild
selecting different versions of TypeScripthttps://github.com/microsoft/TypeScript-Sublime-Plugin#note-using-different-versions-of-typescript
list of editors that have support for TypeScripthttps://github.com/Microsoft/TypeScript/wiki/TypeScript-Editor-Support
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#convert-to-optional-chaining
optional chaininghttps://devblogs.microsoft.com/typescript/announcing-typescript-3-7/#optional-chaining
nullish coalescinghttps://devblogs.microsoft.com/typescript/announcing-typescript-3-7/#nullish-coalescing
check out the pull request for this featurehttps://github.com/microsoft/TypeScript/pull/39135
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#-deprecated--support
Wenlu Wanghttps://github.com/Kingwl
the pull requesthttps://github.com/microsoft/TypeScript/pull/38523
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#partial-semantic-mode-at-startup
Visual Studio Codehttp://code.visualstudio.com/
Visual Studio Code Insidershttp://code.visualstudio.com/insiders
a list of improvementshttps://github.com/microsoft/TypeScript/issues/39035
see the original proposalhttps://github.com/microsoft/TypeScript/issues/37713
the implementing pull requesthttps://github.com/microsoft/TypeScript/pull/38561
the follow-up meta issuehttps://github.com/microsoft/TypeScript/issues/39035
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#smarter-auto-imports
proposal issuehttps://github.com/microsoft/TypeScript/issues/37812
the implementing pull requesthttps://github.com/microsoft/TypeScript/pull/38923
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#our-new-website
The TypeScript websitehttps://www.typescriptlang.org/
We already wrote a bit about our new sitehttps://devblogs.microsoft.com/typescript/announcing-the-new-typescript-website/
file them over on the website’s issue trackerhttps://github.com/microsoft/TypeScript-Website
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#breaking-changes
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#libdts-changes
document.originhttps://developer.mozilla.org/en-US/docs/Web/API/Document/origin
self.originhttps://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/origin
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#properties-overriding-accessors-and-vice-versa-is-an-error
useDefineForClassFieldshttps://www.typescriptlang.org/tsconfig#useDefineForClassFields
Tryhttps://www.typescriptlang.org/play/#code/PTAEAEFMCdoe2gZwFygIwAYAsBOUAmANkwCgBjAGwENFFQAhGyUAbxNFAHNIAXUAMzhwAFAEpW7DqGi8ArtAB26DBgDckgL6TEvAUOEA3KhVmRxbKaBCgAdHc0kt5arVAARGAEsDkACahIAA8eSAVfOkYdCQ5BOFAAXmV1DSA
Tryhttps://www.typescriptlang.org/play/#code/PTAEAEFMCdoe2gZwFygEwDYCMWBQBjAGwENFFQAhUyUAb11FAAd4nQBeULABgG5cAvrgIkyoACIwAlgDdIAE1CQAHgBdIAO3nkqiGvUYBzSKuasAFAEo6DRqGgmArtA1dufW0IFA
the implementing pull requesthttps://github.com/microsoft/TypeScript/pull/37894
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#operands-for-delete-must-be-optional
strictNullCheckshttps://www.typescriptlang.org/tsconfig#strictNullChecks
Tryhttps://www.typescriptlang.org/play/#code/PTAEAEFMCdoe2gZwFygEwHYCcAGAUAJYB2ALjAGYCGAxpKACoAWxA5qAN56igAO8PqRCWisA3HgC+ePOQCuRaiQJwiocgAoAHqiasAlBy6gAJpAA2kMqE0A6PnB7iJQA
the implementing pull requesthttps://github.com/microsoft/TypeScript/pull/37921
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#usage-of-typescripts-node-factory-is-deprecated
read up on the relevant pull request for this changehttps://github.com/microsoft/TypeScript/pull/35282
Variadic Tuple Typeshttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#variadic-tuple-types
Labeled Tuple Elementshttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#labeled-tuple-elements
Class Property Inference from Constructorshttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#class-property-inference-from-constructors
Short-Circuiting Assignment Operatorshttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#short-circuiting-assignment-operators
unknown on catch Clause Bindingshttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#unknown-on-catch-clause-bindings
Custom JSX Factorieshttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#custom-jsx-factories
Speed Improvements in build mode with --noEmitOnErrorhttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#speed-improvements-in-build-mode-with---noemitonerror
--incremental with --noEmithttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#--incremental-with---noemit
Editor Improvementshttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#editor-improvements
Convert to Optional Chaininghttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#convert-to-optional-chaining
/** @deprecated */ Supporthttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#-deprecated--support
Partial Semantic Mode at Startuphttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#partial-semantic-mode-at-startup
Smarter Auto-Importshttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#smarter-auto-imports
Our New Website!https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#our-new-website
Breaking Changeshttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#breaking-changes
lib.d.ts Changeshttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#libdts-changes
Properties Overriding Accessors (and vice versa) is an Errorhttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#properties-overriding-accessors-and-vice-versa-is-an-error
Operands for delete must be optional.https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#operands-for-delete-must-be-optional
Usage of TypeScript’s Node Factory is Deprecatedhttps://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#usage-of-typescripts-node-factory-is-deprecated
by sending a Pull Requesthttps://github.com/microsoft/TypeScript-Website/blob/v2/packages/documentation/copy/en/release-notes/TypeScript 4.0.md
Everyday Typeshttps://www.typescriptlang.org/docs/handbook/2/everyday-types.html
Creating Types from Typeshttps://www.typescriptlang.org/docs/handbook/2/types-from-types.html
More on Functionshttps://www.typescriptlang.org/docs/handbook/2/functions.html
More on Objectshttps://www.typescriptlang.org/docs/handbook/2/objects.html
Narrowinghttps://www.typescriptlang.org/docs/handbook/2/narrowing.html
Variable Declarationshttps://www.typescriptlang.org/docs/handbook/variable-declarations.html
TypeScript in 5 minuteshttps://www.typescriptlang.org/docs/handbook/typescript-in-5-minutes.html
TSConfig Optionshttps://www.typescriptlang.org/tsconfig/
Classeshttps://www.typescriptlang.org/docs/handbook/2/classes.html
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html
Privacyhttps://go.microsoft.com/fwlink/?LinkId=521839
Terms of Usehttps://go.microsoft.com/fwlink/?LinkID=206977
Get Startedhttps://www.typescriptlang.org/docs/
Downloadhttps://www.typescriptlang.org/download/
Communityhttps://www.typescriptlang.org/community/
Playgroundhttps://www.typescriptlang.org/play/
TSConfig Refhttps://www.typescriptlang.org/tsconfig/
Code Sampleshttps://www.typescriptlang.org/play/#show-examples
Why TypeScripthttps://www.typescriptlang.org/why-create-typescript/
Designhttps://www.typescriptlang.org/branding/
Get Helphttps://www.typescriptlang.org/community
Bloghttps://devblogs.microsoft.com/typescript/
GitHub Repohttps://github.com/microsoft/TypeScript/#readme
Community Chathttps://discord.gg/typescript
@TypeScripthttps://twitter.com/TypeScript
Mastodonhttps://fosstodon.org/@TypeScript
Stack Overflowhttps://stackoverflow.com/questions/tagged/typescript
Web Repohttps://github.com/microsoft/TypeScript-Website

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