Ionic3 - Email Composer - Object(...) is not a function - ionic-framework

Question

For Ionic, I'm trying something with emails. So an user presses a button and goes to an email app to send an email with a set 'to', 'subject' and 'body'.
I followed the Ionic doc for EmailComposer : https://ionicframework.com/docs/native/email-composer
So I installed the plugin, followed the 'usage'.
import { EmailComposer } from '#ionic-native/email-composer/ngx';
constructor(private emailComposer: EmailComposer) { }
...
this.emailComposer.isAvailable().then((available: boolean) =>{
if(available) {
//Now we know we can send
}
});
let email = {
to: 'max#mustermann.de',
cc: 'erika#mustermann.de',
bcc: ['john#doe.com', 'jane#doe.com'],
// attachments: [],
subject: 'Cordova Icons',
body: 'How are you? Nice greetings from Leipzig',
isHtml: true
}
// Send a text message using default options
this.emailComposer.open(email);
Only when I press the button. I get error :
ERROR TypeError: Object(...) is not a function
at EmailComposer.open (index.js:58)
I don't know the reason for this. I tried this in a fresh ionic3 project, but I still got the same error.

Answer 1

EmailComposer from #ionic-native/email-composer/ngx is not supporting in Ionic 3. It is supporting in Ionic 4. You need to install EmailComposer from #ionic-native/email-composer which supports for Ionic 3.
Install EmailComposer using below command.
npm install --save #ionic-native/email-composer#4

Answer 2

The problem is you are telling the function what to do but aren't calling the function:
this.emailComposer.isAvailable().then((available: boolean) => {
if(available) {
//Now we know we can send
}
});
You have to name the function and after it, tell it what to do:
sendEmail() {
this.emailComposer.isAvailable().then((available: boolean) => {
if (available) {
}
});
let email = {
to: 'email#domain',
subject: '',
body: '',
isHtml: true
};
this.emailComposer.open(email);
}