Problems initiating Web API File object in test with Babel and Jest - jestjs

Question

While trying to upgrade babel to v7 in an existing test setup with Jest and Enzyme, I have encountered a problem where Web API File is empty. Although it responds to methods like myFile.name.
Packages used:
babel => 7.6.4
jest => 24.9.0
babel-jest => 24.9.0
Not really an expert with babel, but this is my config
Babe config
const env = process.env.NODE_ENV;
const isProd = () => env === 'production';
const isDev = () => env === 'development';
const isTest = () => env === 'test';
const babelPresetEnvOptions = () => {
const options = {};
if (isTest()) {
options.targets = { node: 'current' };
} else {
// Disable polyfill transforms
options.useBuiltIns = false;
// Do not transform modules to CommonJS
options.modules = false;
}
if (isProd()) {
options.forceAllTransforms = true;
}
return options;
};
const presets = [
[require.resolve('#babel/preset-env'), babelPresetEnvOptions()],
[require.resolve('#babel/preset-react'), { development: isDev() }],
];
const plugins = [
[require.resolve('#babel/plugin-proposal-decorators'), { legacy: true }],
[require.resolve('#babel/plugin-proposal-class-properties'), { loose: true }],
require.resolve('#babel/plugin-proposal-object-rest-spread'),
require.resolve('#babel/plugin-transform-react-jsx'),
require.resolve('#babel/plugin-transform-runtime'),
];
if (isTest()) {
// Compiles import() to a deferred require()
plugins.push(require.resolve('babel-plugin-dynamic-import-node'));
} else {
// Adds syntax support for import()
plugins.push(require.resolve('#babel/plugin-syntax-dynamic-import'));
}
module.exports = api => {
api.assertVersion('^7.6');
return {
presets,
plugins,
};
};
Jest setup
"jest": {
"rootDir": "./webpack",
"setupFiles": [
"<rootDir>/test/jestsetup.js"
],
"snapshotSerializers": [
"enzyme-to-json/serializer"
],
"moduleNameMapper": {
"^.+\\.(css|scss)$": "identity-obj-proxy"
},
"transform": {
"^.+\\.(js|jsx)?$": "babel-jest"
}
},
Problem:
When I try to initiate a file object
const lastModified = 1511256180536;
const myImageFile = new File([''], 'pixel.gif', { type: 'image/gif', lastModified });
console.log(myImageFile); // Also results in => File {}
console.log(imageFile.name); // return 'pixel.gif'
The test snapshot fails as shown below, which I can't explain why.
- file={
- File {
- Symbol(impl): FileImpl {
- "_buffer": Object {
- "data": Array [],
- "type": "Buffer",
- },
- "isClosed": false,
- "lastModified": 1511256180536,
- "name": "pixel.gif",
- "type": "image/gif",
- Symbol(wrapper): [Circular],
- },
- }
- }
+ file={File {}}
Even a hint on this would be great.
Babel debug
#babel/preset-env: `DEBUG` option
Using targets:
{
"node": "12.11"
}
Using modules transform: auto
Using plugins:
syntax-async-generators { "node":"12.11" }
syntax-object-rest-spread { "node":"12.11" }
syntax-json-strings { "node":"12.11" }
syntax-optional-catch-binding { "node":"12.11" }
transform-modules-commonjs { "node":"12.11" }
proposal-dynamic-import { "node":"12.11" }
Using polyfills: No polyfills were added, since the `useBuiltIns` option was not set.