jest: how to configure jest for testing javascript applications

A collection of posts on how to configure Jest to add various capabilities. Many of these posts are inspired by Kent C. Dodds’ Testing Javascript course. I also have a growing collection of tips for using Jest.

• Import Modules — how to configure jest to use the import keyword
• Test Environments
• Handling Static Assets — how to handle static assets like css, jpg, etc. with moduleNameMapper
• Using identity-obj-proxy for Asserting on CSS Modules — configuring identity-obj-proxy for asserting on classnames of css modules.
• Using snapshots to protect against regressions — how to use snapshots and configure snapshotSerializers.
• Extending Jest’s Assertion Library — how to extend Jest’s native assertion library
• Configuring Typeahead Hints — how to configure a watch plugin
• Module Resolution — how to resolve modules in non-standard way (e.g., treating an internal directory as a module)
• Watching Projects — a jest plugin for focusing what’s being run, instead of running everything
• Testing Staged Files — how to ensure that jest is run on related files
• Configuring Custom Jest Runners — using jest runners
• Using Multiple Configurations — configuring jest to run multiple configurations in a single test run
• Building Test Abstractions with moduleDirectories — how to use moduleDirectories to abstract away utility functions / helpers for tests
• And an example of abstracting out test configurations with typescript by focusing on RTL and redux-mock store
• Configuring Jest coverage reports
• Configuring Jest for Typescript (with ts-jest)
• Configuring Jest for ESM Modules and Typescript