istanbul-instrumenter-loader

Webpack loader that instruments JavaScript files with istanbul-lib-instrument for code coverage reporting. Latest stable version is 3.0.1 (March 2018). Designed for webpack 2–4, primarily used with Karma and karma-coverage-istanbul-reporter. Supports Babel integration but must run as a post-loader. The loader has been superseded by babel-plugin-istanbul and is no longer actively maintained, but still functional for webpack 3 projects. It validates options via schema-utils but has limited flexibility compared to newer approaches.