Bentley npm Script Suggestions
This document is intended to provide suggestions for writing your own package's npm scripts for things such as building, running tests, and adding code coverage. The iTwin.js-related repositories directly use npm scripts rather than other tools such as gulp. This enables the scripts to be more direct and cut out the "middle-man" that may update more slowly.
The build-tools package includes a set of config files for some of the recommended packages to ease the development process. This includes a config for Typescript and nyc. In addition, a custom mocha reporter is provided. More information about these scripts can be found in the build-tools README.
An ESLint Plugin, @itwin/eslint-plugin, is provided with a recommended configuration.
Building
Suggested Package:
With a properly configured tsconfig.json file, running the TypeScript compiler with tsc should be enough for backend libraries and simple backend agents/services. For more information about tsconfig properties, see the TypeScript website. Frontend services or applications may require the use of Webpack or another more involved build solution.
Cleaning Directories
Suggested Package:
Use rimraf as a cross-platform way to remove output folders (For example: rimraf ./lib). This package functions in a similar manner to the rm -rf command in Unix shells.
Copying Files
Suggested Package:
cpx2 is a cross-platform copy utility for copying globs of files from a source to a destination directory. Useful for copying around files such as test files or assets.
Testing
Suggested Package:
Mocha is a flexible javascript test runner that can be used to run TypeScript test code in two ways: by either running the compiled JavaScript output of the TypeScript tests, or by running the TypeScript tests/source code directly using the ts-node. Running Mocha with ts-node allows us to generate accurate code coverage numbers for the TypeScript source files.
Code Coverage
Suggested Package:
Istanbul can be used together with mocha (in a ts-node configuration) to provide code coverage numbers and reports based on the package's test suite. This can be accomplished by running a ts-node test command directly with nyc (ex: nyc run npm test:tsnode). Several types of reports are available, such as a summary of coverage in the console window or an html output that shows specifically which statements have been covered.
Other useful packages
ts-node A typescript execution environment for code. Can be used to run Mocha tests and useful for generating code coverage percentages and reports.
tsconfig-paths - This may be necessary in multi-package repositories when dependencies are located using a folder's tsconfig "baseUrl" and "paths" attributes. This package is most often used with Mocha and ts-node to run tests directly from the TypeScript source files.
Last Updated: 02 December, 2021