Method replace

packages/mobx/src/types/observablemap.ts:376–452

(values: IObservableMapInitialValues<K, V>)

    }

    replace(values: IObservableMapInitialValues<K, V>): ObservableMap<K, V> {
        // Implementation requirements:
        // - respect ordering of replacement map
        // - allow interceptors to run and potentially prevent individual operations
        // - don't recreate observables that already exist in original map (so we don't destroy existing subscriptions)
        // - don't _keysAtom.reportChanged if the keys of resulting map are indentical (order matters!)
        // - note that result map may differ from replacement map due to the interceptors
        transaction(() => {
            // Convert to map so we can do quick key lookups
            const replacementMap = convertToMap(values)
            const orderedData = new Map()
            // Used for optimization
            let keysReportChangedCalled = false
            // Delete keys that don't exist in replacement map
            // if the key deletion is prevented by interceptor
            // add entry at the beginning of the result map
            for (const key of this.data_.keys()) {
                // Concurrently iterating/deleting keys
                // iterator should handle this correctly
                if (!replacementMap.has(key)) {
                    const deleted = this.delete(key)
                    // Was the key removed?
                    if (deleted) {
                        // _keysAtom.reportChanged() was already called
                        keysReportChangedCalled = true
                    } else {
                        // Delete prevented by interceptor
                        const value = this.data_.get(key)
                        orderedData.set(key, value)
                    }
                }
            }
            // Merge entries
            for (const [key, value] of replacementMap.entries()) {
                // We will want to know whether a new key is added
                const keyExisted = this.data_.has(key)
                // Add or update value
                this.set(key, value)
                // The addition could have been prevent by interceptor
                if (this.data_.has(key)) {
                    // The update could have been prevented by interceptor
                    // and also we want to preserve existing values
                    // so use value from _data map (instead of replacement map)
                    const value = this.data_.get(key)
                    orderedData.set(key, value)
                    // Was a new key added?
                    if (!keyExisted) {
                        // _keysAtom.reportChanged() was already called
                        keysReportChangedCalled = true
                    }
                }
            }
            // Check for possible key order change
            if (!keysReportChangedCalled) {
                if (this.data_.size !== orderedData.size) {
                    // If size differs, keys are definitely modified
                    this.keysAtom_.reportChanged()
                } else {