Today we’re announcing the availability of TypeScript 4.1 Beta!<\/p>\n
To get started using the beta, you can get it through NuGet<\/a>, or use npm with the following command:<\/p>\n You can also get editor support by<\/p>\n For this release, we have some exciting new features, new checking flags, editor productivity updates, and speed improvements. Let’s get a look at what 4.1 has in store for us!<\/p>\n String literal types in TypeScript allow us to model functions and APIs that expect a set of specific strings.<\/p>\n This is pretty nice because string literal types can basically spell-check our string values.<\/p>\n We also like that string literals can be used as property names in mapped types. In this sense, they’re also usable as building blocks.<\/p>\n But there’s another place that that string literal types could be used as building blocks: building other string literal types.<\/p>\nnpm install typescript@beta<\/pre>\n<\/div>\n
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--noUncheckedIndexedAccess<\/code><\/a><\/li>\npaths<\/code> without baseUrl<\/code><\/a><\/li>\ncheckJs<\/code> Implies allowJs<\/code><\/a><\/li>\n@see<\/code> Tag<\/a><\/li>\nTemplate Literal Types<\/h2>\n
function<\/span> setVerticalAlignment<\/span>(<\/span>color<\/span>: \"top\"<\/span> | \"middle\"<\/span> | \"bottom\"<\/span>)<\/span> {<\/span>\r\n \/\/ ...<\/span>\r\n}<\/span>\r\n\r\nsetVerticalAlignment<\/span>(<\/span>\"middel\"<\/span>)<\/span>;<\/span>\r\n\/\/ ~~~~~~~~<\/span>\r\n\/\/ error: Argument of type '\"middel\"' is not assignable to<\/span>\r\n\/\/ parameter of type '\"top\" | \"middle\" | \"bottom\"'.<\/span><\/pre>\n<\/div>\ntype<\/span> Options<\/span> =<\/span> {<\/span>\r\n [<\/span>K<\/span> in<\/span> \"noImplicitAny\"<\/span> | \"strictNullChecks\"<\/span> | \"strictFunctionTypes\"<\/span>]<\/span>?: boolean<\/span>\r\n}<\/span>;<\/span>\r\n\/\/ same as<\/span>\r\n\/\/ type Options = {<\/span>\r\n\/\/ noImplicitAny?: boolean,<\/span>\r\n\/\/ strictNullChecks?: boolean,<\/span>\r\n\/\/ strictFunctionTypes?: boolean<\/span>\r\n\/\/ };<\/span><\/pre>\n<\/div>\n