navigator.platform undefined when running Mocha tests with Brace - reactjs

Question

I'm trying to run tests on React components within Mocha, but I keep stumbling up on this error:
var os = (navigator.platform.match(/mac|win|linux/i) || ["other])[0].toLowerCase();
TypeError: Cannot read property 'match' of undefined
I understand that the error means that the module is having trouble figuring out what platform the code is running on. However this error is being thrown from node_modules/brace/index.js, so it is not something that I have written myself. Is there a way for Mocha to ignore this and continue with the tests?
Here is my package.json:
{
"name": "project",
"version": "0.2.0",
"description": "project",
"scripts": {
"clean:build": "node ./bin/clean.js createdir",
"build:html": "node ./bin/buildHtml.js",
"deployProduction": "node ./bin/deployProduction.js",
"start": "webpack-dev-server --config ./config/webpack.config.dev.js --hot --in line --progress",
"serve": "npm run deployProduction&& supervisor --watch ./production-copy src/js/server",
"prebuild": "npm run clean:build",
"postbuild": "node ./bin/postBuild.js",
"rebuild-win": "set BUILD_TYPE=preview& npm run prebuild & npm run build-win & npm run serve",
"build": "set BUILD_TYPE=final& npm run prebuild & npm run build-win",
"deploy": "npm run build & npm run serve",
"build-win": "set NODE_ENV=production & npm run element-build & npm run build-doc & npm run build:html & webpack -p --config ./config/webpack.config.prod.js --json > webpack.log.json & npm run postbuild",
"lint": "eslint config src/js/**/*.js",
"jscs": "jscs src/js/",
"test": "mocha --compilers js:babel-core/register --require ./test/unit/dom.js --recursive ./test/*.spec.js ",
"test:watch": "npm run test -- --watch",
"element-init": "node node_modules/element-theme/bin/element-theme -i src/js/core/ui/element-theme.css",
"element-build": "node node_modules/element-theme/bin/element-theme -c src/js/core/ui/element-theme.css -o src/js/core/ui/element-theme ",
"build-doc": "node bin/buildDoc.js "
},
"repository": {
"type": "git",
"url": "<our repository>"
},
"license": "MIT",
"bugs": {
"url": "<our url>"
},
"homepage": "<our homepage>",
"dependencies": {
"autoprefixer": "^6.3.6",
"axios": "^0.11.1",
"babel-standalone": "^6.10.3",
"bluebird": "^3.4.0",
"brace": "^0.8.0",
"browserify": "^13.0.1",
"classnames": "2.2.3",
"cls-bluebird": "^1.0.1",
"codemirror": "^5.16.0",
"continuation-local-storage": "^3.1.7",
"dateformat": "^1.0.12",
"diff": "^3.0.1",
"element-theme": "^0.4.0",
"element-ui": "^1.1.5",
"express-history-api-fallback": "^2.0.0",
"filedrop": "^2.0.0",
"fs-extra": "^0.30.0",
"history": "^2.0.2",
"humps": "^1.0.0",
"isomorphic-fetch": "^2.2.1",
"jszip": "^3.0.0",
"jszip-utils": "0.0.2",
"lodash": "^4.11.1",
"material-ui": "^0.16.2",
"materialize-css": "^0.97.6",
"normalizr": "^1.0.0",
"raven-js": "^3.9.1",
"react": "^15.4.2",
"react-ace": "^4.1.4",
"react-dom": "^15.4.2",
"react-redux": "^5.0.2",
"react-router": "^3.0.2",
"react-router-redux": "^4.0.8",
"react-tap-event-plugin": "^2.0.1",
"redux": "^3.4.0",
"redux-logger": "^2.6.1",
"redux-saga": "^0.9.5",
"request": "^2.72.0",
"request-promise": "^3.0.0",
"save-as": "^0.1.7",
"showdown": "^1.4.2",
"three": "^0.79.0",
"vue": "^2.0.5",
"vue-loader": "^9.8.1",
"vue-router": "^2.0.1",
"vue-slider-component": "^2.0.4",
"walk": "^2.3.9"
},
"devDependencies": {
"babel-core": "^6.7.6",
"babel-eslint": "^6.1.0",
"babel-loader": "^6.0.2",
"babel-plugin-react-transform": "^2.0.2",
"babel-polyfill": "^6.6.1",
"babel-preset-airbnb": "^2.2.3",
"babel-preset-es2015": "^6.6.0",
"babel-preset-react": "^6.5.0",
"babel-preset-stage-2": "^6.5.0",
"babel-register": "^6.7.2",
"chai": "^3.5.0",
"chai-jquery": "2.0.0",
"cheerio": "^0.22.0",
"colors": "1.1.2",
"concurrently": "^2.0.0",
"copy-webpack-plugin": "2.1.1",
"css-loader": "0.23.1",
"element-theme-default": "^1.1.5",
"enzyme": "^2.7.1",
"eslint": "^2.13.1",
"eslint-config-airbnb": "^9.0.1",
"eslint-plugin-react": "^5.2.2",
"express": "^4.13.4",
"extract-text-webpack-plugin": "1.0.1",
"file-loader": "0.8.5",
"jquery": "2.2.3",
"jscs": "3.0.3",
"jsdoc-to-markdown": "^2.0.0",
"jsdom": "^9.11.0",
"mocha": "^3.2.0",
"ncp": "^2.0.0",
"node-sass": "3.7.0",
"postcss-loader": "0.8.2",
"react-addons-test-utils": "^15.4.2",
"react-hot-loader": "^1.3.1",
"react-transform-hmr": "^1.0.4",
"redux-devtools": "^3.3.1",
"redux-devtools-dock-monitor": "^1.1.1",
"redux-devtools-log-monitor": "^1.0.11",
"remotedev": "^0.1.2",
"rimraf": "^2.5.2",
"sass-loader": "3.2.0",
"style-loader": "0.13.1",
"url-loader": "0.5.7",
"webpack": "^1.13.0",
"webpack-dev-middleware": "^1.6.1",
"webpack-dev-server": "1.14.1",
"webpack-hot-middleware": "^2.10.0"
}

Answer 1

To solve this, as the OP mentioned you need to set up the navigator in your test setup and include two properties: platform and appName.
Here is a little snip-it of what your test setup script should contain to set this up properly:
var exposedProperties = ['window', 'navigator', 'document'];
global.window = document.defaultView;
global.navigator = {
userAgent: 'node.js',
platform: 'windows', // This can be set to mac, windows, or linux
appName: "Microsoft Internet Explorer", // Be sure to define this as well
};

Answer 2

Found the issue: I was recreating the navigator variable and forgetting to put the platform member inside of it.