add objectize_array method to convert an array of objects to a dictionary of objects by specified key

coretool.js

@@ -10,6 +10,10 @@ module.exports = {
 
   sleep: (ms) => new Promise((resolve, reject) => setTimeout(resolve, ms)),
 
+  objectize_array (arr, key) {
+    return arr.reduce((obj, item) => ({ ...obj, [item[key]]: item }), {})
+  },
+
   deepFreeze (obj) {
     if (typeof obj !== 'object' || obj === null) {
       return obj