Don't needlessly reload resources

ReactNativeClient/lib/ModelCache.js

@@ -0,0 +1,39 @@
+class ModelCache {
+
+	constructor(maxSize) {
+		this.cache_ = [];
+		this.maxSize_ = maxSize;
+	}
+
+	fromCache(ModelClass, id) {
+		for (let i = 0; i < this.cache_.length; i++) {
+			const c = this.cache_[i];
+			if (c.id === id && c.modelType === ModelClass.modelType()) return c
+		}
+		return null;
+	}
+
+	cache(ModelClass, id, model) {
+		if (this.fromCache(ModelClass, model.id)) return;
+		this.cache_.push({
+			id: id,
+			model: model,
+			modelType: ModelClass.modelType(),
+		});
+
+		if (this.cache_.length > this.maxSize_) {
+			this.cache_.splice(0, 1);
+		}
+	}
+
+	async load(ModelClass, id) {
+		const cached = this.fromCache(ModelClass, id);
+		if (cached) return cached.model;
+		const output = await ModelClass.load(id);
+		this.cache(ModelClass, id, output);
+		return output;
+	}
+
+}
+
+module.exports = ModelCache;