139 lines
4.0 KiB
JavaScript
139 lines
4.0 KiB
JavaScript
/**
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* @flow
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*/
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import Reference from './reference.js';
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import { isObject, deepGet, deepExists } from './../../utils';
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/**
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* @link https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot
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*/
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export default class Snapshot {
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ref: Object;
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key: string;
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_value: any;
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_priority: any;
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_childKeys: Array<string>;
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constructor(ref: Reference, snapshot: Object) {
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this.ref = ref;
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this.key = snapshot.key;
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// internal use only
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this._value = snapshot.value;
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this._priority = snapshot.priority === undefined ? null : snapshot.priority;
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this._childKeys = snapshot.childKeys || [];
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}
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/**
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* Extracts a JavaScript value from a DataSnapshot.
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* @link https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#val
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* @returns {any}
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*/
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val(): any {
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// clone via JSON stringify/parse - prevent modification of this._value
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if (isObject(this._value) || Array.isArray(this._value)) return JSON.parse(JSON.stringify(this._value));
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return this._value;
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}
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/**
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* Gets another DataSnapshot for the location at the specified relative path.
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* @param path
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* @link https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#forEach
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* @returns {Snapshot}
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*/
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child(path: string): Snapshot {
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const value = deepGet(this._value, path);
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const childRef = this.ref.child(path);
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return new Snapshot(childRef, {
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value,
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key: childRef.key,
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exists: value !== null,
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// todo this is wrong - child keys needs to be the ordered keys, from FB
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// todo potential solution is build up a tree/map of a snapshot and its children
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// todo natively and send that back to JS to be use in this class.
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childKeys: isObject(value) ? Object.keys(value) : [],
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});
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}
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/**
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* Returns true if this DataSnapshot contains any data.
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* @link https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#exists
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* @returns {boolean}
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*/
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exists(): boolean {
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return this._value !== null;
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}
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/**
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* Enumerates the top-level children in the DataSnapshot.
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* @link https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#forEach
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* @param action
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*/
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forEach(action: (key: any) => any): boolean {
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if (!this._childKeys.length) return false;
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let cancelled = false;
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for (let i = 0, len = this._childKeys.length; i < len; i++) {
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const key = this._childKeys[i];
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const childSnapshot = this.child(key);
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const returnValue = action(childSnapshot);
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if (returnValue === true) {
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cancelled = true;
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break;
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}
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}
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return cancelled;
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}
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/**
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* Gets the priority value of the data in this DataSnapshot.
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* @link https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#getPriority
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* @returns {String|Number|null}
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*/
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getPriority(): string | number | null {
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return this._priority;
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}
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/**
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* Returns true if the specified child path has (non-null) data.
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* @link https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#hasChild
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* @param path
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* @returns {Boolean}
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*/
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hasChild(path: string): boolean {
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return deepExists(this._value, path);
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}
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/**
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* Returns whether or not the DataSnapshot has any non-null child properties.
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* @link https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#hasChildren
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* @returns {boolean}
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*/
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hasChildren(): boolean {
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return this.numChildren() > 0;
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}
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/**
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* Returns the number of child properties of this DataSnapshot.
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* @link https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#numChildren
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* @returns {Number}
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*/
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numChildren(): number {
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if (!isObject(this._value)) return 0;
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return Object.keys(this._value).length;
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}
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/**
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* Returns a JSON-serializable representation of this object.
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* @link https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#toJSON
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* @returns {any}
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*/
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toJSON(): any {
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return this.val();
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}
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}
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