How to use Karma and Jest together in unit testing React application? - reactjs

Question

I am testing a React application already developed. The application has some unit test cases written in Karma but I am going to use Jest to unit test the application as it is the new framework, developed by facebook for testing React. The problem I am facing is because of file .babelrc. For Jest to run fine the content of .babelrc file should be as follows:
// .babelrc
{
"presets": ["es2015", "react"]
}
But my existing application uses Karma and has the babelrc file content as below:
{
"presets": [
"es2015",
"react",
"stage-0"
]
, "plugins": [
"transform-object-rest-spread"
, "transform-decorators-legacy"
, "transform-es2015-modules-amd"
]
}
The current babelrc file is not allowing Jest to run properly and causes error. But the thing is I cant modify its content as required by Jest since it will hamper my Karma test cases to stop running. Is there a way I can use the both at same time until i rewrite existing test cases in Jest?

Answer 1

I was able to run both Karma and Jest together so thought of sharing. I configured the babelrc file as follows:
{
"env": {
"test": {
"presets": [
"es2015",
"react"
]
},
"development": {
"presets": [
"es2015",
"react"
],
"plugins": [
............
]
},
"production": {
"presets": [
"es2015",
"react"
],
"plugins": [
...............
]
}
}
}