{"id":2304,"date":"2019-07-02T15:49:15","date_gmt":"2019-07-02T14:49:15","guid":{"rendered":"https:\/\/solidt.eu\/site\/?p=2304"},"modified":"2019-07-02T15:49:16","modified_gmt":"2019-07-02T14:49:16","slug":"typescript-datasource","status":"publish","type":"post","link":"https:\/\/solidt.eu\/site\/typescript-datasource\/","title":{"rendered":"Typescript datasource"},"content":{"rendered":"\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"js\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ tslint:disable-next-line: import-blacklist\nimport {  Observable, BehaviorSubject, Subject } from \"rxjs\";\nimport { map } from \"rxjs\/operators\";\n\nexport interface IDataSource&lt;T> {\n    readonly data: Observable&lt;T[]>;\n    readonly loading: Observable&lt;boolean>;\n    load(): PromiseLike&lt;T[]>;\n    reload(): PromiseLike&lt;T[]>;\n    filter(filterFn: (obj: any) => boolean);\n}\nexport class DataSource&lt;T> implements IDataSource&lt;T> {\n    private _loading = new BehaviorSubject&lt;boolean>(false);\n    private _dataArr: T[];\n    private _data: Subject&lt;T[]>;\n    private _dataPromise: PromiseLike&lt;T[]>;\n    private _filterFn: (obj: any) => boolean;\n    constructor(private _dataFn: () => PromiseLike&lt;T[]>) {\n        this._filterFn = (obj: any) => true;\n        this._data = new BehaviorSubject&lt;T[]>([]);\n    }\n    async load(reload: boolean = false) {\n        if (!this._dataPromise || reload) {\n            return this.reload();\n        }\n        return await this._dataPromise;\n    }\n    async reload() {\n        this._loading.next(true);\n        this._dataPromise = this._dataFn();\n        Promise.resolve(this._dataPromise)\n            .then((d) => {\n                this._dataArr = d;\n                this._data.next(d);\n                return d;\n            }).finally(() => this._loading.next(false));\n        return await this._dataPromise;\n    }\n    get data(): Observable&lt;T[]> {\n        return this._data.pipe(map((arr: T[]) => Array.from(arr).filter(this._filterFn)));\n    }\n    get loading(): Observable&lt;boolean> {\n        return this._loading.asObservable();\n    }\n    filter(filterFn: (obj: any) => boolean) {\n        if (!filterFn) {\n            filterFn = (obj: any) => true;\n        }\n        this._filterFn = filterFn;\n        if (this._dataArr) {\n            this._data.next(this._dataArr);\n        }\n    }\n}\n<\/pre>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ usage\n        this.dataSource = new DataSource&lt;IDebtorOrder>(async () => {\n            const completeOrderHistory = await appDomain.IRequestStoreDebtorOrder.getLastOrders(3);\n            return completeOrderHistory;\n        });\n        this.dataSource.load();<\/pre>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"html\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">&lt;ng-container *ngFor=\"let order of dataSource.data | async\">\n        &lt;app-order-history-item [debtorOrder]=\"order\">&lt;\/app-order-history-item>\n    &lt;\/ng-container><\/pre>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2304","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/solidt.eu\/site\/wp-json\/wp\/v2\/posts\/2304","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/solidt.eu\/site\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/solidt.eu\/site\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/solidt.eu\/site\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/solidt.eu\/site\/wp-json\/wp\/v2\/comments?post=2304"}],"version-history":[{"count":1,"href":"https:\/\/solidt.eu\/site\/wp-json\/wp\/v2\/posts\/2304\/revisions"}],"predecessor-version":[{"id":2305,"href":"https:\/\/solidt.eu\/site\/wp-json\/wp\/v2\/posts\/2304\/revisions\/2305"}],"wp:attachment":[{"href":"https:\/\/solidt.eu\/site\/wp-json\/wp\/v2\/media?parent=2304"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/solidt.eu\/site\/wp-json\/wp\/v2\/categories?post=2304"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/solidt.eu\/site\/wp-json\/wp\/v2\/tags?post=2304"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}