## istanbul-lib-instrument [](https://travis-ci.org/istanbuljs/istanbul-lib-instrument) Istanbul instrumenter library. Version 1.1.x now implements instrumentation using `Babel`. The implementation is inspired by prior art by @dtinth as demonstrated in the `__coverage__` babel plugin. It provides 2 "modes" of instrumentation. - The old API that is mostly unchanged (except for incompatibilities noted) and performs the instrumentation using babel as a library. - A `programVisitor` function for the Babel AST that can be used by a Babel plugin to emit instrumentation for ES6 code directly without any source map processing. This is the preferred path for babel users. The Babel plugin is called `babel-plugin-istanbul`. Incompatibilities and changes to instrumentation behavior can be found in [v0-changes.md](v0-changes.md).