n8n/packages/workflow/src/AugmentObject.ts

import type { IDataObject } from './Interfaces';

const augmentedObjects = new WeakSet<object>();
function augment<T>(value: T): T {
	if (
		typeof value !== 'object' ||
		value === null ||
		value instanceof RegExp ||
		augmentedObjects.has(value)
	)
		return value;

	// Track augmented objects to prevent infinite recursion in cases where an object contains circular references
	augmentedObjects.add(value);

	if (value instanceof Date) return new Date(value.valueOf()) as T;

	// eslint-disable-next-line @typescript-eslint/no-use-before-define
	if (Array.isArray(value)) return augmentArray(value) as T;

	// eslint-disable-next-line @typescript-eslint/no-use-before-define
	return augmentObject(value) as T;
}

export function augmentArray<T>(data: T[]): T[] {
	let newData: unknown[] | undefined = undefined;

	function getData(): unknown[] {
		if (newData === undefined) {
			newData = [...data];
		}
		return newData;
	}

	return new Proxy(data, {
		deleteProperty(target, key: string) {
			return Reflect.deleteProperty(getData(), key);
		},
		get(target, key: string, receiver): unknown {
			const value = Reflect.get(newData !== undefined ? newData : target, key, receiver) as unknown;
			const newValue = augment(value);
			if (newValue !== value) {
				newData = getData();
				Reflect.set(newData, key, newValue);
				return newValue;
			}
			return value;
		},
		getOwnPropertyDescriptor(target, key) {
			if (newData === undefined) {
				return Reflect.getOwnPropertyDescriptor(target, key);
			}

			if (key === 'length') {
				return Reflect.getOwnPropertyDescriptor(newData, key);
			}
			return { configurable: true, enumerable: true };
		},
		has(target, key) {
			return Reflect.has(newData !== undefined ? newData : target, key);
		},
		ownKeys(target) {
			return Reflect.ownKeys(newData !== undefined ? newData : target);
		},
		set(target, key: string, newValue: unknown) {
			if (newValue !== null && typeof newValue === 'object') {
				// Always proxy all objects. Like that we can check in get simply if it
				// is a proxy and it does then not matter if it was already there from the
				// beginning and it got proxied at some point or set later and so theoretically
				// does not have to get proxied
				newValue = new Proxy(newValue, {});
			}

			return Reflect.set(getData(), key, newValue);
		},
	});
}

export function augmentObject<T extends object>(data: T): T {
	const newData = {} as IDataObject;
	const deletedProperties: Array<string | symbol> = [];

	return new Proxy(data, {
		get(target, key: string, receiver): unknown {
			if (deletedProperties.indexOf(key) !== -1) {
				return undefined;
			}

			if (newData[key] !== undefined) {
				return newData[key];
			}

			// eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
			const value = Reflect.get(target, key, receiver);
			const newValue = augment(value);
			if (newValue !== value) {
				Object.assign(newData, { [key]: newValue });
				return newValue;
			}

			return value;
		},
		deleteProperty(target, key: string) {
			if (key in newData) {
				delete newData[key];
			}
			if (key in target) {
				deletedProperties.push(key);
			}

			return true;
		},
		set(target, key: string, newValue: unknown) {
			if (newValue === undefined) {
				if (key in newData) {
					delete newData[key];
				}
				if (key in target) {
					deletedProperties.push(key);
				}
				return true;
			}

			newData[key] = newValue as IDataObject;

			const deleteIndex = deletedProperties.indexOf(key);
			if (deleteIndex !== -1) {
				deletedProperties.splice(deleteIndex, 1);
			}

			return true;
		},
		ownKeys(target) {
			return [...new Set([...Reflect.ownKeys(target), ...Object.keys(newData)])].filter(
				(key) => deletedProperties.indexOf(key) === -1,
			);
		},

		// eslint-disable-next-line @typescript-eslint/no-unused-vars
		getOwnPropertyDescriptor(k) {
			return {
				enumerable: true,
				configurable: true,
			};
		},
	});
}