Add @dougal/organisations NodeJS module.

Abstracts the concept of Organisations in the new permissions model.

lib/modules/@dougal/organisations/Organisation.js

@@ -0,0 +1,75 @@
+
+class Organisation {
+
+	constructor (data) {
+
+		this.read = !!data?.read;
+		this.write = !!data?.write;
+		this.edit = !!data?.edit;
+
+		this.other = {};
+
+		return new Proxy(this, {
+			get (target, prop) {
+				if (prop in target) {
+					return target[prop]
+				} else {
+					return target.other[prop];
+				}
+			},
+
+			set (target, prop, value) {
+				const oldValue = target[prop] !== undefined ? target[prop] : target.other[prop];
+				const newValue = Boolean(value);
+
+				if (["read", "write", "edit"].includes(prop)) {
+					target[prop] = newValue;
+				} else {
+					target.other[prop] = newValue;
+				}
+
+				return true;
+			}
+		});
+	}
+
+	toJSON () {
+		return {
+			read: this.read,
+			write: this.write,
+			edit: this.edit,
+			...this.other
+		}
+	}
+
+	toString (replacer, space) {
+		return JSON.stringify(this.toJSON(), replacer, space);
+	}
+
+	/** Limit the operations to only those allowed by `other`
+	 */
+	filter (other) {
+		const filteredOrganisation = new Organisation();
+
+		filteredOrganisation.read = this.read && other.read;
+		filteredOrganisation.write = this.write && other.write;
+		filteredOrganisation.edit = this.edit && other.edit;
+
+		return filteredOrganisation;
+	}
+
+	intersect (other) {
+		return this.filter(other);
+	}
+
+}
+
+
+if (typeof module !== 'undefined' && module.exports) {
+    module.exports = Organisation; // CJS export
+}
+
+// ESM export
+if (typeof exports !== 'undefined' && !exports.default) {
+    exports.default = Organisation; // ESM export
+}