Testing a TypeScript File Read / Write operations app using Jest JS, Mocks, Unit Tests

In this video, I run through how I tested a TypeScript application that reads and writes files to the disk. It's an interesting challenge and results in using jest mocks and the node tmpdir functions.

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[dawid_dahl]

As a TS and Jest user I thank you a lot for making this video! 🙏🏻

[jms]

Thanks, passed through a lot of videos and only yours worked for me without many imports. Appreciate it

[mgehad]

Awesome explanation. Thank you <3 Greetings from Egypt.

[hkolvoort]

Great video! Like the step wise approach, easy to follow, very well explained!

[nairanvac]

Thank you so much for this! Very helpful.

[Luis-omvc]

Thanks man, You saved me, Greetings from Mexico

[abhishes]

8:10. I wrote the test case as shown on this screen. and it throws an error "test/src/mytest.test.ts:1:1 - error TS1208: 'mytest.test.ts' cannot be compiled under '--isolatedModules' because it is considered a global script file. Add an import, export, or an empty 'export {}' statement to make it a module."

[carlosdelgado]

Thanks for the video very informative, as suggestion increase the font size a little bit or maybe don't record the whole screen so it's easier for us to read

[ragipgashi]

I am trying to test my .ts files in an app, but after transpiling to the .js I get an error in the browser: uncaught referenceerror: module is not defined at....
Do you have a solution please???

[dawid_dahl]

Question. I noticed you didn’t mock the side effecty fs library here, and actually called the real thing, causing real files to be written and read.

I am not aware of the tmpdir from Node os. Is it there for this reason, so that we do not make new actually persisting files every time we run our tests?