function JSONCov(runner, output) {
  var self = this
    , output = 1 == arguments.length ? true : output;

  Base.call(this, runner);

  var tests = []
    , failures = []
    , passes = [];

  runner.on('test end', function(test){
    tests.push(test);
  });

  runner.on('pass', function(test){
    passes.push(test);
  });

  runner.on('fail', function(test){
    failures.push(test);
  });

  runner.on('end', function(){
    var cov = global._$jscoverage || {};
    var result = self.cov = map(cov);
    result.stats = self.stats;
    result.tests = tests.map(clean);
    result.failures = failures.map(clean);
    result.passes = passes.map(clean);
    if (!output) return;
    process.stdout.write(JSON.stringify(result, null, 2 ));
  });
}
Initialize a new `JsCoverage` reporter.

@param {Runner} runner
@param {Boolean} output
@api public