Don't call setState if unmounted before font loads

fbshipit-source-id: 2ff8070

createIconSet.js

@@ -1,10 +1,8 @@
 import React from 'react';
 import { Text } from 'react-native';
 import { Font } from 'expo';
-import createIconSet
-  from './vendor/react-native-vector-icons/lib/create-icon-set';
-import createIconButtonComponent
-  from './vendor/react-native-vector-icons/lib/icon-button';
+import createIconSet from './vendor/react-native-vector-icons/lib/create-icon-set';
+import createIconButtonComponent from './vendor/react-native-vector-icons/lib/icon-button';
 
 export default function(glyphMap, fontName, expoAssetId) {
   const expoFontName = Font.style(fontName, {
@@ -22,12 +20,17 @@ export default function(glyphMap, fontName, expoAssetId) {
     };
 
     async componentWillMount() {
+      this._mounted = true;
       if (!this.state.fontIsLoaded) {
         await Font.loadAsync(font);
-        this.setState({ fontIsLoaded: true });
+        this._mounted && this.setState({ fontIsLoaded: true });
       }
     }
 
+    componentWillUnmount() {
+      this._mounted = false;
+    }
+
     setNativeProps(props) {
       if (this._icon) {
         this._icon.setNativeProps(props);

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@expo/vector-icons",
-  "version": "5.0.0",
+  "version": "5.1.0",
   "description": "Built-in support for 10 popular icon fonts and the tooling to create your own Icon components from your font and glyph map. This is a wrapper around react-native-vector-icons to make it compatible with Expo.",
   "main": "index.js",
   "scripts": {},