babel-plugin-rewire-ignore-coverage

This plugin disables rewire injected methods from istanbul coverage counts.
We get ES6/7 syntax and JSX transpiling out of the box with babel-loader (webpack module). The rewire plugin to babel is used to mock out other components when unit testing a component. The rewiring injects some code (setters/getters/resetters) when the system under test accesses the other dependent mocked components. The coverage sweep reported those injected methods as not covered by tests. This new babel-plugin-rewire-ignore-coverage plugin marks those injected code functions to be ignored by istanbul, after the rewiring
Works with Babel 6.x

Example

In

function _get__(variableName) {
   if (_RewiredData__ === undefined || _RewiredData__[variableName] === undefined) {
       return _get_original__(variableName);
   } else {
       var value = _RewiredData__[variableName];

       if (value === INTENTIONAL_UNDEFINED) {
           return undefined;
       } else {
           return value;
       }
   }
}

function _get_original__(variableName) {
   switch (variableName) {
   case 'React':
       return _react2.default;
   }

   return undefined;
}

function _assign__(variableName, value) {
   if (_RewiredData__ === undefined || _RewiredData__[variableName] === undefined) {
       return _set_original__(variableName, value);
   } else {
       return _RewiredData__[variableName] = value;
   }
}

function _set_original__(variableName, _value) {
   switch (variableName) {}

   return undefined;
}

function _update_operation__(operation, variableName, prefix) {
   var oldValue = _get__(variableName);

   var newValue = operation === '++' ? oldValue + 1 : oldValue - 1;

   _assign__(variableName, newValue);

   return prefix ? newValue : oldValue;
}

function _set__(variableName, value) {
   if ((typeof variableName === 'undefined' ? 'undefined' : _typeof(variableName)) === 'object') {
       Object.keys(variableName).forEach(function(name) {
           _RewiredData__[name] = variableName[name];
       });
   } else {
       if (value === undefined) {
           _RewiredData__[variableName] = INTENTIONAL_UNDEFINED;
       } else {
           _RewiredData__[variableName] = value;
       }

       return function() {
           _reset__(variableName);
       };
   }
}

function _reset__(variableName) {
   delete _RewiredData__[variableName];
}

function _with__(object) {
   var rewiredVariableNames = Object.keys(object);
   var previousValues = {};

   function reset() {
       rewiredVariableNames.forEach(function(variableName) {
           _RewiredData__[variableName] = previousValues[variableName];
       });
   }

   return function(callback) {
       rewiredVariableNames.forEach(function(variableName) {
           previousValues[variableName] = _RewiredData__[variableName];
           _RewiredData__[variableName] = object[variableName];
       });
       var result = callback();

       if (!!result && typeof result.then === 'function') {
           result.then(reset).catch(reset);
       } else {
           reset();
       }

       return result;
   };
}

Out

// istanbul ignore next
function _get__(variableName) {
    if (_RewiredData__ === undefined || _RewiredData__[variableName] === undefined) {
        return _get_original__(variableName);
    } else {
        var value = _RewiredData__[variableName];

        if (value === INTENTIONAL_UNDEFINED) {
            return undefined;
        } else {
            return value;
        }
    }
}

// istanbul ignore next
function _get_original__(variableName) {
    switch (variableName) {
    case 'React':
        return _react2.default;
    }

    return undefined;
}

// istanbul ignore next
function _assign__(variableName, value) {
    if (_RewiredData__ === undefined || _RewiredData__[variableName] === undefined) {
        return _set_original__(variableName, value);
    } else {
        return _RewiredData__[variableName] = value;
    }
}

// istanbul ignore next
function _set_original__(variableName, _value) {
    switch (variableName) {}

    return undefined;
}

// istanbul ignore next
function _update_operation__(operation, variableName, prefix) {
    var oldValue = _get__(variableName);

    var newValue = operation === '++' ? oldValue + 1 : oldValue - 1;

    _assign__(variableName, newValue);

    return prefix ? newValue : oldValue;
}

// istanbul ignore next
function _set__(variableName, value) {
    if ((typeof variableName === 'undefined' ? 'undefined' : _typeof(variableName)) === 'object') {
        Object.keys(variableName).forEach(function(name) {
            _RewiredData__[name] = variableName[name];
        });
    } else {
        if (value === undefined) {
            _RewiredData__[variableName] = INTENTIONAL_UNDEFINED;
        } else {
            _RewiredData__[variableName] = value;
        }

        return function() {
            _reset__(variableName);
        };
    }
}

// istanbul ignore next
function _reset__(variableName) {
    delete _RewiredData__[variableName];
}

// istanbul ignore next
function _with__(object) {
    var rewiredVariableNames = Object.keys(object);
    var previousValues = {};

    function reset() {
        rewiredVariableNames.forEach(function(variableName) {
            _RewiredData__[variableName] = previousValues[variableName];
        });
    }

    return function(callback) {
        rewiredVariableNames.forEach(function(variableName) {
            previousValues[variableName] = _RewiredData__[variableName];
            _RewiredData__[variableName] = object[variableName];
        });
        var result = callback();

        if (!!result && typeof result.then === 'function') {
            result.then(reset).catch(reset);
        } else {
            reset();
        }

        return result;
    };
}

Installation

$ npm install babel-plugin-rewire-ignore-coverage

Usage

Via .babelrc (Recommended)

.babelrc

{
  "plugins": ["rewire", "rewire-ignore-coverage"]
}

Via CLI

$ babel --plugins rewire-ignore-coverage  script.js

Via Node API

require("babel-core").transform("code", {
  plugins: ["rewire-ignore-coverage"]
});

Via Karma config

webpack: {
     devtool: "source-map",
     module: {
         loaders: [
             {
                 // all js src and test files get treated by babel
                 test: /\.js?$/,
                 include: [
                     path.resolve(__dirname, "client/src"),
                     path.resolve(__dirname, "client/test")
                 ],
                 exclude: [nodeModulesPath],
                 loader: "babel-loader",
                 query: {
                     plugins: ['babel-plugin-rewire', 
                               'babel-plugin-rewire-ignore-coverage']
                 }
             },