replacing lodash with deepCopy implementation

utils/arrayUtils.js

@@ -15,3 +15,37 @@ function common(a, b) {
 function unique(array) {
   return [...new Set(array)];
 }
+
+// deep copy for Arrays (and other objects)
+function deepCopy(obj) {
+  const id = x=>x;
+  const dcTArray = a => a.map(id);
+  const dcObject = x => Object.fromEntries(Object.entries(x).map(([k,d])=>[k,dcAny(d)]));
+  const dcAny = x => x instanceof Object ? (cf.get(x.constructor)||id)(x) : x;
+  // don't map keys, probably this is what we would expect
+  const dcMapCore = m => [...m.entries()].map(([k,v])=>[k, dcAny(v)]);
+
+  const cf = new Map([
+      [Int8Array, dcTArray],
+      [Uint8Array, dcTArray],
+      [Uint8ClampedArray, dcTArray],
+      [Int16Array, dcTArray],
+      [Uint16Array, dcTArray],
+      [Int32Array, dcTArray],
+      [Uint32Array, dcTArray],
+      [Float32Array, dcTArray],
+      [Float64Array, dcTArray],
+      [BigInt64Array, dcTArray],
+      [BigUint64Array, dcTArray],
+      [Map, m => new Map(dcMapCore(m))],
+      [WeakMap, m => new WeakMap(dcMapCore(m))],
+      [Array, a => a.map(dcAny)],
+      [Set, s => [...s.values()].map(dcAny)],
+      [Date, d => new Date(d.getTime())],
+      [Object, dcObject],
+      // other types will be referenced
+      // ... extend here to implement their custom deep copy
+  ]);
+
+  return dcAny(obj);
+}