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January 22, 2023 21:30
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How to setup Jest with TypeScript
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| 1. npm install Jest | |
| - This command is the Jest package | |
| 2. npm install ts-jest | |
| - This enables jest with TypeScript annotations | |
| 3. npm i --save-dev @types/jest | |
| - Use with step 4 | |
| 4. Addd "@types/jest" to your tsconfig.json: | |
| { "compilerOptions": { "types": [""@types/jest"] } } | |
| - This fixes your 'test' and 'expect' not found errors | |
| 5. Create some files named xxx.test.ts anywhere in your project. Usually these files will be auto-detected by jest for testing without needing to configure a jest config file. | |
| 6. Add this to package.json: | |
| "jest": { | |
| "preset": "ts-jest" | |
| } | |
| in package.json | |
| (eg. add it after the 'dependencies' section, 'devDependencies' section.... | |
| 7. Add: | |
| describe('Description for group of tests', () => { | |
| test('A test', () => { | |
| }); | |
| test('A second test', () => { | |
| }); | |
| }); | |
| You don't need to import anything for these keywords, because you have jest configured already | |
| 8. Run 'jest' in your terminal somewhere in your repository, Jest will automatically detect all xx.test.ts files and run them | |
| 9. For isolatedModules: true typescript libraries, add export {} to the end of your file. | |
| 10. Versions used: | |
| // Caetgorized under dependencies | |
| "ts-jest": "^29.0.5" | |
| "jest": "^29.3.1", | |
| // Categorized under dev dependencies | |
| "@types/jest": "^29.2.6", | |
| "typescript": "^4.5.4", |
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