@darwino/darwino/src/JstoreCursor.js

A set of Javascript classes and utilities

/* 
 * (c) Copyright Darwino Inc. 2014-2017.
 */
import {fetchJson,makeQueryString,addQueryString} from './Fetch';
import DEV_OPTIONS from "./dev";

const USE_POST = false; // For mostly debug purposes

/*
 * JSON store cursor.
 */
export default class JstoreCursor {

    constructor() {
        this._params = {}
        this._queryString = {};
        this._process = this._process.bind(this)
    }

    _stringify(s) {
        return typeof s==='object' ?  JSON.stringify(s) : s;
    }

    queryString() {
        return this._queryString;
    }
        
    queryParams(params) {
        if(params) {
            for(let k in params) {
                if(params.hasOwnProperty(k)) {
                    if(params[k]) {
                        this._params[k] = this._stringify(params[k])
                    } else {
                        delete this._params[k];
                    }
                }
            }
        }
        return this;
    }

    database(database) {
        this.database = database;
        return this;
    }

    store(store) {
        this.store = store;
        return this;
    }

    jsonTree(t) {
        if(t) this._queryString.jsontree=true
        else delete this._queryString.jsontree;
    }

    key(key) {
        return this.queryParams({key});
    }

    query(query) {
        return this.queryParams({query});
    }

    categoryCount(categorycount) {
        return this.queryParams({categorycount});
    }

    params(params) {
        return this.queryParams({params});
    }

    orderby(orderBy,descending) {
        if(Array.isArray(orderBy)) {
            orderBy = orderBy.join(',')
        }
        let o = {orderby:orderBy}
        if(descending) o.descending=true
        return this.queryParams(o);
    }

    ftsearch(ftsearch) {
        return this.queryParams({ftsearch});
    }

    extract(extract) {
        return this.queryParams({extract});
    }

    aggregator(aggregator) {
        return this.queryParams({aggregator});
    }

    skip(skip) {
        return this.queryParams({skip});
    }

    limit(limit) {
        return this.queryParams({limit});
    }

    name(name) {
        return this.queryParams({name});
    }

    _process(e) {
        // This might be done on the server...
        let r = e.json;
        delete e.json
        r.__meta = e
        if(r.__meta.children) {
            r.__meta.children = r.__meta.children.map(this._process);
        }
        return r;
    }
    
    fetch() {
        // Use POST to not have length constraints
        const url = this.computeUrl('/entries',USE_POST,true)
        const opts = this.computeOptions();

        return fetchJson(
            url, opts
        ).then(json => {
            return json.map(this._process);
        })
    }

    fetchCount() {
        // Use POST to not have length constraints
        const url = this.computeUrl('/count',USE_POST,true)
        const opts = this.computeOptions();

        return fetchJson(
            url, opts
        ).then(json => {
            return json.count;
        })
    }

    computeUrl(urlPart,post,queryString) {
        let url = `${DEV_OPTIONS.serverPrefix}$darwino-jstore/databases/${encodeURIComponent(this.database)}`
        if(this.store) {
            url += `/stores/${encodeURIComponent(this.store)}`
        }
        url += urlPart
        if(!post) {
            url = addQueryString(url,makeQueryString(this._params)) 
        }
        if(queryString) {
            url = addQueryString(url,makeQueryString(this._queryString)) 
        }
        return url;
    }
    computeOptions() {
        // MS Edge is picky about the presence of a body param in GET, even if empty
        if(USE_POST) {
            return { method: 'POST', body: JSON.stringify(this._params||{})};
        } else {
            return { method: 'GET' };
        }
    }

    getDataLoader() {
        return (num,pagesize) => {
            this.skip(num*pagesize)
            this.limit(pagesize)
            return this.fetch();
        }
    }
}