You may need an appropriate loader to handle this file type about react-diff-viewer HOT 2 CLOSED

{
  "presets": [
    "babel-preset-react",
    ["es2015", { "modules": false }],
    "babel-preset-stage-0"
  ],
  // "presets": ["es2015", "stage-0", "react"],
  "env": {
    "test": {
      "plugins": [
        "transform-es2015-modules-commonjs",
        "transform-decorators-legacy",
        "babel-plugin-react-html-attrs",
        "babel-plugin-transform-decorators-legacy",
        "babel-plugin-transform-class-properties",
        "@babel/plugin-transform-spread",
        "@babel/plugin-proposal-class-properties",
        "@babel/preset-env",
        "@babel/preset-react"
      ]
    }
  }
}