[Q1/Product] Improve SDK code quality and test coverage

[bonomat]

Problem

In the last objective alignment meeting we agreed that we need to invest time and effort into improving the overall code quality of the comit-js-sdk.

Goal

The comit-js-sdk should be fully tested independently from comit-rs (i.e. outside of the e2e tests of comit-rs).

Recommendation

• Write tests Focus on the critical parts first, i.e. everywhere where we do any form of calculation or number transformation from one type into another.
• Review how to make the sdk robust to runtime failures (cnd call times out, functions throwing errors)
• Introduce a static code analysis tool and
• Introduce a test coverage tool to measure progress of code quality.

[yosriady]

Code coverage

Since you're already using Jest, you can generate code coverage by adding the flag --coverage. No additional setup needed. Jest can collect code coverage information from entire projects, including untested files.

Change https://github.com/comit-network/comit-js-sdk/blob/master/package.json#L12 to add jest --coverage

If you're using vscode, you can use a plugin to highlight you code which are uncovered.

[yosriady]

Static analysis

We should use https://eslint.org/.