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.