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I have a TypeScript project, where the test are written in TypeScript. I want to use mocha to directly test TS files. I'm using ts-node for that, as described in ts-node#mocha.
In the project I'm using a JS library which doesn't have TS type definitions. So I created a d.ts file for that. Everything works well when compiling and running the projects. However mocha fails with:
% yarn mocha --require ts-node/register --require source-map-support/register ./test/*.ts
src/client.ts:3:26 - error TS7016: Could not find a declaration file for module 'algosdk'. '/home/robert/projects/algorand/ts-mocha/node_modules/algosdk/index.js' implicitly has an 'any' type.
Try `npm install @types/algosdk` if it exists or add a new declaration (.d.ts) file containing `declare module 'algosdk';`
3 import * as algosdk from "algosdk";
It seams that ts-node doesn't recognize the d.ts files.
The only solution which works is to use require instead of import statement, but this will not link the types to algosdk.
This is the project structure (also in github):
├── build <-- JS from compiled TS go here
├── node_modules
├── package.json
├── src
├── @types <-- d.ts files
├── test
├── tsconfig.json
The tsconfig.json:
{
"compilerOptions": {
"target": "es2017",
"lib": ["esnext"],
"module": "commonjs",
"esModuleInterop": true,
"allowSyntheticDefaultImports": true,
"strict": true,
"outDir": "./build",
"typeRoots" : ["./@types", "node_modules/@types"]
},
"exclude": ["**/node_modules"],
"include": [
"src",
"test",
"@types"
]
}
I confirm that the problem is related to ts-node, not to mocha. Running:
yarn ts-node src/client.ts
returns the same error.
697
The nice way to do this is to add a "test" npm script in package. json that calls mocha with the right arguments. This way your package. json also describes your test structure.
TS-Mocha has one only dependency - ts-node, which is used as a TypeScript runtime to execute tests that can import and run imported TypeScript source files as well. It is a thin wrapper that run node process with mocha and set up ts-node environment to handle .
Declaration files, if you're not familiar, are just files that describe the shape of an existing JavaScript codebase to TypeScript. By using declaration files (also called . d. ts files), you can avoid misusing libraries and get things like completions in your editor.
The error "Could not find declaration file for module" occurs when TypeScript cannot find the type declaration for a module. To solve the error, install the types for the module by running the command from the error message, e.g. npm install -D @types/module-name .
you can add the following configuration to tsconfig.json file.
"ts-node": {
"files": true
},
it works well on my side.
54
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