Like many good solutions in programming, you achieve this by adding a layer of indirection. Specifically, what we can do here is add a table between action tags (i.e. “Example” and “Another”) and their respective payloads. type ActionPayloadTable = { “Example”: { example: true }, “Another”: { another: true }, } then what we can … Read more
Yes this is possible. You can find all information here: https://www.typescriptlang.org/docs/handbook/declaration-files/templates/global-modifying-module-d-ts.html The important part is this: declare global { /*~ Here, declare things that go in the global namespace, or augment *~ existing declarations in the global namespace */ interface String { fancyFormat(opts: StringFormatOptions): string; } }
The compiler will widen string literal type to string, unless some specific conditions are met as explained in github issues and PR, or const assertion is used for literal value. Const assertions appeared in TypeScript 3.4: const KeyToVal = { MyKey1: ‘myValue1’, MyKey2: ‘myValue2’, } as const; type Keys = keyof typeof KeyToVal; type Values … Read more
If you need to overwrite an existing property declaration to change the type, you’ll need to fork the @types/expo types. The easiest way is probably to copy the index.d.ts file into your typings directory and uninstall the original @types/expo package. Or you can use a tool such as Braid (disclosure: I am a Braid contributor) … Read more
It’s very simple. Just install the definitions that you need via npm. For example if you need lodash you can do: npm install –save @types/lodash Once it’s installed you can use it right away in your project. Typescript will resolve the typings for the installed @types package from the node_modules/@types folder by default. There’s no … Read more
I was having a similar problem, but I could not add –files, because I run ts-node by registering the module through mocha (i.e. mocha -r ts-node/register …). I could solve it by adding a files and a ts-node section to tsconfig.json like this: // tsconfig.json { “ts-node”: { “files”: true }, “files”: [ “src/index.ts”, “src/global.d.ts” … Read more
As of TypeScript 2.0, typings is no longer required. The npm organization is an entity to setup a developers team. I believe Microsoft setup the @types organization in npm and added the TypeScript developer team to the organization. Packages on under the @types organization are published automatically from DefinitelyTyped using the types-publisher tool as per … Read more
No, this is not possible in TypeScript as of TS4.1. There are two issues I see; one might be overcome with a change to the TypeScript standard library typings for Array.prototype.map(), but the other would require a fairly large change to the type system to work in general and cannot currently be handled in a … Read more
Create node_modules folder under your src, then put typings of module(s) you want to overwrite inside: ├── node_modules │ └── … │ └── src ├── index.ts ├── … your codes … │ └── node_modules └── <module-to-be-overwritten> └── index.d.ts No need to modify compilerOptions in tsconfig.json. Read How TypeScript resolves modules section in https://www.typescriptlang.org/docs/handbook/module-resolution.html.
“Magically available interfaces” or global types is highly discouraged and should mostly be left to legacy. Also, you should not be using ambient declaration files (e.g. d.ts files) for code that you are writing. These are meant to stand-in the place of external non-typescript code (essentially filling in the typescript types into js code so … Read more