Gets or sets the schema settings for DataSource. Schema settings describe the type of the data and allow modifications to the data during retrieval. If the initialization options of the component specify a schema, this property contains the initial schema object.

var dataSource = new shield.DataSource({
    schema: {
        type: "json", //default
        data: "result.items",
        total: "result.totalItems",
        fields: {
            id: { path: "productId", type: "number" },
            name: { path: "productName", type: "string" },
            category: { path: "", type: "string" },
            available: { path: "productAvailable", type: "boolean" },
            price: { path: "unitPrice", type: "number" },
            added: { path: "dateAdded", type: "date" }

console.log(dataSource.schema);   //schema is the above object
//redefine parts of the initial schema = { "path": "productNumber", type: "number" };