added rest component

+import ARCS from '../engine/arcs.js';
+
+let RestWrapper;
+
+/**
+ * @class RestWrapper
+ * @classdesc A wrapper for REST requests
+ * 
+ */
+
+RestWrapper = ARCS.Component.create(
+    function() {
+
+        const request = async function(method, url, obj) {
+            const requestOptions = {
+                method: method,
+                headers: {'Content-Type': 'application/json'},
+            };
+
+            if (obj) requestOptions.body = JSON.stringify(obj);
+
+            let response = await fetch(url, requestOptions);
+            if (! response.ok) return null;
+            let data = await response.json();
+            if (data === null)
+                return response.status;
+            return data;
+        };
+
+        /**
+         * Read REST request (GET)
+         * This idea is to obtain a resource through a specific URL.
+         * The resource is then sent through the <b>send</b> signal.
+         * @slot 
+         * @emits send
+         * @param {string} url 
+         */
+        this.read = async function(url) {
+            let output = await request('GET', url);
+            this.emit('send', output);
+        };
+
+        /**
+         * Create REST request (PUT)
+         * The passed object is created through the PUT request
+         * @slot
+         * @param {string} url 
+         * @param {Object} obj 
+         */
+        this.create = async function(url, obj) {
+            let output = await request('PUT', url, obj);            
+        };
+
+        /**
+         * Update REST request (POST)
+         * The passed object is updated through the POST request
+         * @slot
+         * @param {string} url 
+         * @param {Object} obj 
+         */
+        this.update = async function(url, obj) {
+            let output = await request('POST', url, obj);
+        };
+
+        /**
+         * Delete REST request (DELETE)
+         * The resource is destroyed through the request
+         * @param {string} url 
+         */
+        this.delete = async function(url) {
+            let output = await request('DELETE',url);
+        };
+    },
+    ['create','read','update','delete'],
+    ['send']
+
+
+    /* 
+        Reminder of REST API:
+        - GET: read
+        - PUT: create
+        - POST: update
+        - DELETE: delete    
+    */
+
+);
+
+
+export default {RestWrapper};
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