How to set up auto-fix on save by using the project’s Eslint config with VS Code

This is a quick instruction to set up auto-fix on save by using the project’s eslint config with VS Code. It works for both TS and JS.

1. Install ESLint plugin for VS Code.

2. Add config to VS code

Go to Code -> Preference -> Settings (or press cmd + ,).

Search codeActionsOnSave, click edit in settings.json and add the config below.



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  "editor.codeActionsOnSave": {

    "source.fixAll.eslint": true

  },

  "eslint.validate": ["javascript", "typescript"]
Front-End
TypeScript: type aliases to check type equality

This post is to analyse how the type equality check by using type aliases proposed by Matt Pocock in his twitter post. These type aliases allow us to elegantly express type equality checks in unit tests. All we need to do is to pass the output and expected types in …

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If you are getting a type error with it.only in Jest, it could be due to incorrect TypeScript typings or incompatible versions of Jest and TypeScript. To resolve this issue, you can try the following steps: Make sure you have the latest versions of Jest and its TypeScript typings installed …

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Here’s an example of a Yup validation logic where the first input field is optional but, if filled, it must contain only alphabetic characters, and the second input field is required: import * as Yup from “yup”; const validationSchema = Yup.object().shape({ firstField: Yup.string().matches(/^[A-Za-z]*$/, { message: “First field must contain only …