“Maximum call stack size exceeded” while running with PhantomJS

Error message:

    PhantomJS 1.9.1 (Mac OS X) ERROR
        RangeError: Maximum call stack size exceeded.
        at /.../node_modules/karma-chai/node_modules/chai/chai.js:2863
    PhantomJS 1.9.1 (Mac OS X): Executed 0 of 0 ERROR (0.026 secs / 0 secs

Workaround described at https://github.com/chaijs/chai/issues/107.