Matteo Pagliazzi
49 lines
1.9 KiB
JavaScript
49 lines
1.9 KiB
JavaScript
import get from 'lodash/get';
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import axios from 'axios';
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// Return an object used to describe, in the app state, an
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// async resource loaded from the server with its data and status.
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export function asyncResourceFactory () {
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return {
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loadingStatus: 'NOT_LOADED', // NOT_LOADED, LOADING, LOADED
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data: null,
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};
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}
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export function loadAsyncResource ({
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store, path, url, deserialize, forceLoad = false,
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}) {
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if (!store) throw new Error('"store" is required and must be the application store.');
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if (!path) throw new Error('The path to the resource in the application state is required.');
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if (!url) throw new Error('The resource\'s url on the server is required.');
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if (!deserialize) throw new Error('A response deserialization function named must be passed as "deserialize".');
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const resource = get(store.state, path);
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if (!resource) throw new Error(`No resouce found at path "${path}".`);
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const { loadingStatus } = resource;
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if (loadingStatus === 'LOADED' && !forceLoad) {
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return Promise.resolve(resource);
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} if (loadingStatus === 'LOADING') {
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return new Promise((resolve, reject) => {
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const resourceWatcher = store.watch(state => get(state, `${path}.loadingStatus`), newLoadingStatus => {
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resourceWatcher(); // remove the watcher
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if (newLoadingStatus === 'LOADED') {
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return resolve(resource);
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}
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return reject(); // TODO add reason?
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});
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});
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} if (loadingStatus === 'NOT_LOADED' || forceLoad) {
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return axios.get(url).then(response => { // TODO support more params
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resource.loadingStatus = 'LOADED';
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// deserialize can be a promise
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return Promise.resolve(deserialize(response)).then(deserializedData => {
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resource.data = deserializedData;
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return resource;
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});
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});
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}
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return Promise.reject(new Error(`Invalid loading status "${loadingStatus} for resource at "${path}".`));
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}
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