CODEWITHSUNDEEP
node.jsjestjsts-jestjest-fetch-mock
BreenDeen
BreenDeen

Reputation: 732

Unable to mock utility function using import.meta to read file in Jest test

I am reading a a file using import.meta to resolve the directory which fails when trying to mock it in a function. Here is the part of the code which I want to mock

                  // readFileUtil
                  const __filename = fileURLToPath(import.meta.url);
                  const __dirname = path.dirname(__filename);
                  
                  export async function readFile(fileName: string){
                      try {
                       const data = await fs.promises.readFile(fileName, 'utf8')
                       return data
                      } catch (err) {
                        console.log(err);
                      }
                   }

I am then using the code above to read a file like this in some code:

                import readFileUtils from '../file-utils'
                import  dataProcessor from '../data/processor 
                
                function processData(fileName:string){
                   const data = await fs.promises.readFile(fileName, 'utf8')
                   //rest of code uses data
                }

I then wrote a Jest test which tests the processData function like this

                import readFileUtils from '../file-utils'
                import  dataProcessor from '../data/processor 
                
                jest.mock('../file-utils)' 
                describe('Data Processing suite' () => {
                    const fileName = 'resources/data.xml
                    processData(fileName) 
                }

Unfortunately I get the following error

The 'import.meta' meta-property is only allowed when the '--module' option is 'es2020', 'es2022'...etc

I have no idea how to solve this issue. I did a lot of online searches but everything I tried does not work. I did the following:

              {
              "compilerOptions": {
                 "target": "esnext",
                 "module": "esnext",
               ...

I also installed 'npm install ts-jest-mock-import-meta' but none of these solutions worked

Please help

Upvotes: -1

Views: 620

Answers (1)

BreenDeen
BreenDeen

Reputation: 732

I was able to get solve the import.meta error issue. By doing the following.

First, I installed the following

npm install @babel/preset-typescript --save-dev

Next, I added created a file, babel.config.js and added the following code;

          module.exports = {
             presets: [
                ["@babel/preset-env", { targets: { node: "current" } }],
                 "@babel/preset-typescript",
              ],
         };

I am still unable to get the mocking of the file reading function to work.

Upvotes: 1

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