basant307/AI_Governance_Project

1const copyProperty = (to, from, property, ignoreNonConfigurable) => {2	// `Function#length` should reflect the parameters of `to` not `from` since we keep its body.3	// `Function#prototype` is non-writable and non-configurable so can never be modified.4	if (property === 'length' || property === 'prototype') {5		return;6	}7 8	// `Function#arguments` and `Function#caller` should not be copied. They were reported to be present in `Reflect.ownKeys` for some devices in React Native (#41), so we explicitly ignore them here.9	if (property === 'arguments' || property === 'caller') {10		return;11	}12 13	const toDescriptor = Object.getOwnPropertyDescriptor(to, property);14	const fromDescriptor = Object.getOwnPropertyDescriptor(from, property);15 16	if (!canCopyProperty(toDescriptor, fromDescriptor) && ignoreNonConfigurable) {17		return;18	}19 20	Object.defineProperty(to, property, fromDescriptor);21};22 23// `Object.defineProperty()` throws if the property exists, is not configurable and either:24// - one its descriptors is changed25// - it is non-writable and its value is changed26const canCopyProperty = function (toDescriptor, fromDescriptor) {27	return toDescriptor === undefined || toDescriptor.configurable || (28		toDescriptor.writable === fromDescriptor.writable29		&& toDescriptor.enumerable === fromDescriptor.enumerable30		&& toDescriptor.configurable === fromDescriptor.configurable31		&& (toDescriptor.writable || toDescriptor.value === fromDescriptor.value)32	);33};34 35const changePrototype = (to, from) => {36	const fromPrototype = Object.getPrototypeOf(from);37	if (fromPrototype === Object.getPrototypeOf(to)) {38		return;39	}40 41	Object.setPrototypeOf(to, fromPrototype);42};43 44const wrappedToString = (withName, fromBody) => `/* Wrapped ${withName}*/\n${fromBody}`;45 46const toStringDescriptor = Object.getOwnPropertyDescriptor(Function.prototype, 'toString');47const toStringName = Object.getOwnPropertyDescriptor(Function.prototype.toString, 'name');48 49// We call `from.toString()` early (not lazily) to ensure `from` can be garbage collected.50// We use `bind()` instead of a closure for the same reason.51// Calling `from.toString()` early also allows caching it in case `to.toString()` is called several times.52const changeToString = (to, from, name) => {53	const withName = name === '' ? '' : `with ${name.trim()}() `;54	const newToString = wrappedToString.bind(null, withName, from.toString());55	// Ensure `to.toString.toString` is non-enumerable and has the same `same`56	Object.defineProperty(newToString, 'name', toStringName);57	const {writable, enumerable, configurable} = toStringDescriptor; // We destructue to avoid a potential `get` descriptor.58	Object.defineProperty(to, 'toString', {value: newToString, writable, enumerable, configurable});59};60 61export default function mimicFunction(to, from, {ignoreNonConfigurable = false} = {}) {62	const {name} = to;63 64	for (const property of Reflect.ownKeys(from)) {65		copyProperty(to, from, property, ignoreNonConfigurable);66	}67 68	changePrototype(to, from);69	changeToString(to, from, name);70 71	return to;72}73