Added error sub package

source/errors.mjs

@@ -0,0 +1,45 @@
+import { inspect } from 'node:util';
+
+// § GROUP: Resolving errors
+
+export class Item_Unresolvable extends Error {
+	constructor(data) {
+		const { resolver, item } = data;
+		const type = item === null ? 'null' : typeof item;
+		super(`Cannot resolve item ${inspect(item)} of type "${type}" using resolver ${resolver}`);
+		this.data = data;
+	}
+}
+
+
+// § GROUP: Storage errors
+
+export class Not_Storable_Error extends Error {
+	constructor(data) {
+		const { storage, value, property, id } = data;
+		const type = value === null ? 'null' : typeof value;
+		const location = property ? `property "${property}" of record #${id}` : `record #${id}`;
+		super(`Cannot store value of type "${type}" in ${location}: ${inspect(value)}`);
+		this.data = data;
+	}
+}
+
+export class Not_Mutable_Error extends Error {
+	constructor(data) {
+		const { storage, value, property, id } = data;
+		const type = value === null ? 'null' : typeof value;
+		const location = property ? `property "${property}" of record #${id}` : `record #${id}`;
+		super(`Cannot set ${location}: record is immutable (tried to store value of type "${type}": ${inspect(value)})`);
+		this.data = data;
+	}
+}
+
+export class No_Such_Object_Index_Error extends Error {
+	constructor(data) {
+		const { storage, property, id } = data;
+		const location = property ? `property "${property}" of record #${id}` : `record #${id}`;
+		super(`Cannot get ${location}: no such record index`);
+		this.data = data;
+	}
+}
+