I have been using Ionic Framework for a while but I have recently come across this error `plugin_not_installed` for the Health Kit plugin which I know I have based on my `ionic cordova plugin list` output.

```
$ ionic cordova plugin list
> cordova plugin ls
com.telerik.plugins.healthkit 0.5.5 "HealthKit"
cordova-plugin-apprate 1.3.0 "AppRate"
cordova-plugin-badge 0.8.5 "Badge"
cordova-plugin-device 1.1.4 "Device"
cordova-plugin-dialogs 1.3.4 "Notification"
cordova-plugin-globalization 1.0.8 "Globalization"
cordova-plugin-google-analytics 1.8.3 "Google Universal Analytics Plugin"
cordova-plugin-inappbrowser 1.7.2 "InAppBrowser"
cordova-plugin-ionic-webview 1.1.16 "cordova-plugin-ionic-webview"
cordova-plugin-local-notification 0.9.0-beta.1 "LocalNotification"
cordova-plugin-splashscreen 4.0.3 "Splashscreen"
cordova-plugin-statusbar 2.3.0 "StatusBar"
cordova-plugin-whitelist 1.3.1 "Whitelist"
ionic-plugin-keyboard 2.2.1 "Keyboard"

```

My code is wrapped in `platform.ready()` so I know that everything is loaded. I also have my health kit code that is throwing the error in a `healthKit.available()` and a `healthKit.requestAuthorization` which have no error.

```
getWeight.then(function () {
    alert("Healthkit is ready!");
    alert(weight);
    healthKitReady = true;
 }).catch(function(err) {
     if (err) {
         console.log(err); // This is where the error is returned.
     }
  });

```

The function getWeight is this:

```
const getWeight = new Promise(function(resolve, reject) {
    var error;
    healthKit.readWeight({
        unit: "lb"
    }).then(function (out) {
        weight = Math.round(out.value);
        alert("weight: " + weight);
        resolve(weight);
    }, function (err) {
        error = err;
        reject(error);
    });
});

```

Just in case this is a version issue this is the output for ionic info:

```
cli packages: (/usr/local/share/.config/yarn/global/node_modules)

    @ionic/cli-utils  : 1.19.0
    ionic (Ionic CLI) : 3.19.0

global packages:

    cordova (Cordova CLI) : 7.1.0 

local packages:

    @ionic/app-scripts : 3.1.4
    Cordova Platforms  : ios 4.5.4
    Ionic Framework    : ionic-angular 3.9.2

System:

    ios-deploy : 1.9.2 
    ios-sim    : 6.1.2 
    Node       : v8.9.1
    npm        : 2.15.12 
    OS         : macOS High Sierra
    Xcode      : Xcode 9.2 Build version 9C40b 

Environment Variables:

    ANDROID_HOME : not set

Misc:

    backend : pro

```