added utilities

utils/index.js

@@ -0,0 +1,112 @@
+export const isArray = function(a) {
+    return (!!a) && (a.constructor === Array);
+};
+
+export const isObject = function(a) {
+    return (!!a) && (a.constructor === Object);
+};
+
+export  const isDate = function(o) {
+    return o instanceof Object && o.constructor === Date;
+  }
+
+export const has = function(o,p){
+    let has = true
+    for (const prop of p) {
+        has = o.hasOwnProperty(prop)
+        if(!has) break;
+    }
+    return has;
+}
+export const  querablePromise = function(promise) {
+    // Don't modify any promise that has been already modified.
+    if (promise.isPending) return promise;
+  
+    // Setup our initial state.
+    const state = {
+      isPending: true,
+      isRejected: false,
+      isResolved: false,
+  
+      // Specified so that we'll generate accessor functions for them.
+      err: undefined,
+      val: undefined,
+    };
+  
+    // We must actually wait for the promise to either resolve or reject,
+    // wrap that value, then let it continue on.
+    const result = promise.then(
+      function(val) {
+        state.isResolved = true;
+        state.isPending = false;
+        state.val = val;
+        return val;
+      }, 
+      function(err) {
+        state.isRejected = true;
+        state.isPending = false;
+        state.err = err;
+        throw err;
+      }
+    );
+  
+    for (const val of Object.keys(state)) {
+      result[val] = function() { return state[val]; };
+    }
+  
+    return result;
+  }
+  
+  async function get(name, keyPath, transArray) {
+
+		let isValidInput = true
+		let validInput = []
+		
+		if(isObject(transArray) && has(transArray, ['name', 'keyPath'])){
+			isValidInput = true
+			validInput.push(transArray)
+		}else if(isArray(transArray)){
+			for (const o of transArray) {
+				isValidInput = has(o, ['name', 'keyPath'])
+				if(!isValidInput)
+				break;
+			}
+		}else{
+			isValidInput = false;
+		}
+
+		let db = await this.getDb();
+
+		return new Promise((resolve, reject) => {
+
+			if(!isValidInput) reject("Invalid Input");
+
+			let trans = db.transaction([...validInput.map(v => v.name)],'readonly');
+			trans.oncomplete = () => {
+				resolve(output);
+			};
+			let output = []
+
+			for (const o of validInput) {
+				let store = trans.objectStore(o.name);
+				// let tr = {};
+				
+				store.openCursor().onsuccess = e => {
+					let cursor = e.target.result;
+					if (cursor) {
+						if(o.keyPath == cursor.value['abbreviation'])
+							output.push(cursor.value)
+						// tr = cursor.value
+						cursor.continue();
+					}
+				};
+			}
+			trans.onerror = e => {
+				reject(e)
+			}
+			trans.onabort = e => {
+				reject(e)
+			}
+
+		});
+	}