source: node_modules/immer/src/utils/common.ts@ ba17441

import {
        DRAFT_STATE,
        DRAFTABLE,
        Objectish,
        Drafted,
        AnyObject,
        AnyMap,
        AnySet,
        ImmerState,
        ArchType,
        die,
        StrictMode
} from "../internal"

export const getPrototypeOf = Object.getPrototypeOf

/** Returns true if the given value is an Immer draft */
/*#__PURE__*/
export function isDraft(value: any): boolean {
        return !!value && !!value[DRAFT_STATE]
}

/** Returns true if the given value can be drafted by Immer */
/*#__PURE__*/
export function isDraftable(value: any): boolean {
        if (!value) return false
        return (
                isPlainObject(value) ||
                Array.isArray(value) ||
                !!value[DRAFTABLE] ||
                !!value.constructor?.[DRAFTABLE] ||
                isMap(value) ||
                isSet(value)
        )
}

const objectCtorString = Object.prototype.constructor.toString()
const cachedCtorStrings = new WeakMap()
/*#__PURE__*/
export function isPlainObject(value: any): boolean {
        if (!value || typeof value !== "object") return false
        const proto = Object.getPrototypeOf(value)
        if (proto === null || proto === Object.prototype) return true

        const Ctor =
                Object.hasOwnProperty.call(proto, "constructor") && proto.constructor
        if (Ctor === Object) return true

        if (typeof Ctor !== "function") return false

        let ctorString = cachedCtorStrings.get(Ctor)
        if (ctorString === undefined) {
                ctorString = Function.toString.call(Ctor)
                cachedCtorStrings.set(Ctor, ctorString)
        }

        return ctorString === objectCtorString
}

/** Get the underlying object that is represented by the given draft */
/*#__PURE__*/
export function original<T>(value: T): T | undefined
export function original(value: Drafted<any>): any {
        if (!isDraft(value)) die(15, value)
        return value[DRAFT_STATE].base_
}

/**
 * Each iterates a map, set or array.
 * Or, if any other kind of object, all of its own properties.
 *
 * @param obj The object to iterate over
 * @param iter The iterator function
 * @param strict When true (default), includes symbols and non-enumerable properties.
 *               When false, uses looseiteration over only enumerable string properties.
 */
export function each<T extends Objectish>(
        obj: T,
        iter: (key: string | number, value: any, source: T) => void,
        strict?: boolean
): void
export function each(obj: any, iter: any, strict: boolean = true) {
        if (getArchtype(obj) === ArchType.Object) {
                // If strict, we do a full iteration including symbols and non-enumerable properties
                // Otherwise, we only iterate enumerable string properties for performance
                const keys = strict ? Reflect.ownKeys(obj) : Object.keys(obj)
                keys.forEach(key => {
                        iter(key, obj[key], obj)
                })
        } else {
                obj.forEach((entry: any, index: any) => iter(index, entry, obj))
        }
}

/*#__PURE__*/
export function getArchtype(thing: any): ArchType {
        const state: undefined | ImmerState = thing[DRAFT_STATE]
        return state
                ? state.type_
                : Array.isArray(thing)
                ? ArchType.Array
                : isMap(thing)
                ? ArchType.Map
                : isSet(thing)
                ? ArchType.Set
                : ArchType.Object
}

/*#__PURE__*/
export function has(thing: any, prop: PropertyKey): boolean {
        return getArchtype(thing) === ArchType.Map
                ? thing.has(prop)
                : Object.prototype.hasOwnProperty.call(thing, prop)
}

/*#__PURE__*/
export function get(thing: AnyMap | AnyObject, prop: PropertyKey): any {
        // @ts-ignore
        return getArchtype(thing) === ArchType.Map ? thing.get(prop) : thing[prop]
}

/*#__PURE__*/
export function set(thing: any, propOrOldValue: PropertyKey, value: any) {
        const t = getArchtype(thing)
        if (t === ArchType.Map) thing.set(propOrOldValue, value)
        else if (t === ArchType.Set) {
                thing.add(value)
        } else thing[propOrOldValue] = value
}

/*#__PURE__*/
export function is(x: any, y: any): boolean {
        // From: https://github.com/facebook/fbjs/blob/c69904a511b900266935168223063dd8772dfc40/packages/fbjs/src/core/shallowEqual.js
        if (x === y) {
                return x !== 0 || 1 / x === 1 / y
        } else {
                return x !== x && y !== y
        }
}

/*#__PURE__*/
export function isMap(target: any): target is AnyMap {
        return target instanceof Map
}

/*#__PURE__*/
export function isSet(target: any): target is AnySet {
        return target instanceof Set
}
/*#__PURE__*/
export function latest(state: ImmerState): any {
        return state.copy_ || state.base_
}

/*#__PURE__*/
export function shallowCopy(base: any, strict: StrictMode) {
        if (isMap(base)) {
                return new Map(base)
        }
        if (isSet(base)) {
                return new Set(base)
        }
        if (Array.isArray(base)) return Array.prototype.slice.call(base)

        const isPlain = isPlainObject(base)

        if (strict === true || (strict === "class_only" && !isPlain)) {
                // Perform a strict copy
                const descriptors = Object.getOwnPropertyDescriptors(base)
                delete descriptors[DRAFT_STATE as any]
                let keys = Reflect.ownKeys(descriptors)
                for (let i = 0; i < keys.length; i++) {
                        const key: any = keys[i]
                        const desc = descriptors[key]
                        if (desc.writable === false) {
                                desc.writable = true
                                desc.configurable = true
                        }
                        // like object.assign, we will read any _own_, get/set accessors. This helps in dealing
                        // with libraries that trap values, like mobx or vue
                        // unlike object.assign, non-enumerables will be copied as well
                        if (desc.get || desc.set)
                                descriptors[key] = {
                                        configurable: true,
                                        writable: true, // could live with !!desc.set as well here...
                                        enumerable: desc.enumerable,
                                        value: base[key]
                                }
                }
                return Object.create(getPrototypeOf(base), descriptors)
        } else {
                // perform a sloppy copy
                const proto = getPrototypeOf(base)
                if (proto !== null && isPlain) {
                        return {...base} // assumption: better inner class optimization than the assign below
                }
                const obj = Object.create(proto)
                return Object.assign(obj, base)
        }
}

/**
 * Freezes draftable objects. Returns the original object.
 * By default freezes shallowly, but if the second argument is `true` it will freeze recursively.
 *
 * @param obj
 * @param deep
 */
export function freeze<T>(obj: T, deep?: boolean): T
export function freeze<T>(obj: any, deep: boolean = false): T {
        if (isFrozen(obj) || isDraft(obj) || !isDraftable(obj)) return obj
        if (getArchtype(obj) > 1 /* Map or Set */) {
                Object.defineProperties(obj, {
                        set: dontMutateMethodOverride,
                        add: dontMutateMethodOverride,
                        clear: dontMutateMethodOverride,
                        delete: dontMutateMethodOverride
                })
        }
        Object.freeze(obj)
        if (deep)
                // See #590, don't recurse into non-enumerable / Symbol properties when freezing
                // So use Object.values (only string-like, enumerables) instead of each()
                Object.values(obj).forEach(value => freeze(value, true))
        return obj
}

function dontMutateFrozenCollections() {
        die(2)
}

const dontMutateMethodOverride = {
        value: dontMutateFrozenCollections
}

export function isFrozen(obj: any): boolean {
        // Fast path: primitives and null/undefined are always "frozen"
        if (obj === null || typeof obj !== "object") return true
        return Object.isFrozen(obj)
}