Ionic : undefined is not a constructor FileReader

Question

I have a problem when I create a FileReader (from @ionic-native/file) instance :

let f = new FileReader();

The following error occur :

TypeError: undefined is not a constructor (evaluating 'new __WEBPACK_IMPORTED_MODULE_2__ionic_native_file__["FileReader"]()')

I dont understand why !

My config is :

• nodejs v8.9.1
• npm : v5.5.&
• ionic : 3.9.3
• angular : v5.0.1
• iOS emulator

For more informations I use this code :

private readFile(file: any) {
     const reader = new FileReader();
     reader.onloadend = () => {
        const formData = new FormData();
        const imgBlob = new Blob([reader.result], {type: file.type});
        formData.append('file', imgBlob, file.name);
        this.postData(formData);
    };
    reader.readAsArrayBuffer(file);
 }

An error occurs on new FileReader()

Thanks.

Answer 1

The Cordova polyfill saves the original FileReader in FileReader._realReader You can reassign it by doing:

let fr= new FileReader(); 
let rfr = fr._realReader;

FileReader = rfr.constructor;