Added column-oriented JSON output method

finos · texodus · Aug 14, 2018 · Aug 14, 2018 · Aug 14, 2018 · Aug 14, 2018
commit 9ed5a6af61b93e783e00ba46dd5839aaf65e379e
diff --git a/packages/perspective/src/js/api.js b/packages/perspective/src/js/api.js
@@ -54,6 +54,8 @@ function view(worker, table_name, config) {
 
 view.prototype.to_json = async_queue('to_json');
 
+view.prototype.to_columns = async_queue('to_columns');
+
 view.prototype.to_csv = async_queue('to_csv');
 
 view.prototype.schema = async_queue('schema');

diff --git a/packages/perspective/src/js/perspective.js b/packages/perspective/src/js/perspective.js
@@ -563,7 +563,7 @@ const to_format = async function (options, formatter) {
                 if (this.config.row_pivot[0] !== 'psp_okey') {
                     let col_name = "__ROW_PATH__";
                     let row_path = this.ctx.unity_get_row_path(start_row + ridx);
-                    formatter.initColumnValue(row, col_name)
+                    formatter.initColumnValue(data, row, col_name)
                     for (let i = 0; i < row_path.size(); i++) {
                         const value = __MODULE__.scalar_vec_to_val(row_path, i);
                         formatter.addColumnValue(data, row, col_name, value);
@@ -586,8 +586,36 @@ const to_format = async function (options, formatter) {
 
     return formatter.formatData(data, options.config)
 }
+
+/**
+ * Serializes this view to JSON data in a column-oriented format.
+ *
+ * @async
+ *
+ * @param {Object} [options] An optional configuration object.
+ * @param {number} options.start_row The starting row index from which
+ * to serialize.
+ * @param {number} options.end_row The ending row index from which
+ * to serialize.
+ * @param {number} options.start_col The starting column index from which
+ * to serialize.
+ * @param {number} options.end_col The ending column index from which
+ * to serialize.
+ *
+ * @returns {Promise<Array>} A Promise resolving to An array of Objects
+ * representing the rows of this {@link view}.  If this {@link view} had a
+ * "row_pivots" config parameter supplied when constructed, each row Object
+ * will have a "__ROW_PATH__" key, whose value specifies this row's
+ * aggregated path.  If this {@link view} had a "column_pivots" config
+ * parameter supplied, the keys of this object will be comma-prepended with
+ * their comma-separated column paths.
+ */
+view.prototype.to_columns = async function (options) {
+    return to_format.call(this, options, formatters.jsonTableFormatter);
+}
+
 /**
- * Serializes this view to JSON data in a standard format.
+ * Serializes this view to JSON data in a row-oriented format.
  *
  * @async
  *
@@ -609,7 +637,7 @@ const to_format = async function (options, formatter) {
  * parameter supplied, the keys of this object will be comma-prepended with
  * their comma-separated column paths.
  */
-view.prototype.to_json = async function(options) {
+view.prototype.to_json = async function (options) {
     return to_format.call(this, options, formatters.jsonFormatter);
 }
 

diff --git a/packages/perspective/src/js/view_formatters.js b/packages/perspective/src/js/view_formatters.js
@@ -12,7 +12,7 @@ import papaparse from "papaparse";
 const jsonFormatter = {
     initDataValue: () => [],
     initRowValue: () => ({}),
-    initColumnValue: (row, colName) => row[colName] = [],
+    initColumnValue: (data, row, colName) => row[colName] = [],
     setColumnValue: (data, row, colName, value) => row[colName] = value,
     addColumnValue: (data, row, colName, value) => row[colName].unshift(value),
     addRow: (data, row) => data.push(row),
@@ -23,7 +23,27 @@ const csvFormatter = Object.assign({}, jsonFormatter, {
     formatData: (data, config) => papaparse.unparse(data, config)
 });
 
+const jsonTableFormatter = {
+    initDataValue: () => new Object(),
+    initRowValue: () => {},
+    setColumnValue: (data, row, colName, value) => {
+        data[colName] = data[colName] || [];
+        data[colName].push(value)
+    },
+    addColumnValue: (data, row, colName, value) => {
+        data[colName] = data[colName] || [];
+        data[colName][data[colName].length - 1].unshift(value);
+    },
+    initColumnValue: (data, row, colName) => {
+        data[colName] = data[colName] || [];
+        data[colName].push([]);
+    },
+    addRow: (data, row) => {},
+    formatData: data => data
+}
+
 export default {
     jsonFormatter,
+    jsonTableFormatter,
     csvFormatter
 };
diff --git a/packages/perspective/test/config/test_node.config.js b/packages/perspective/test/config/test_node.config.js
@@ -12,4 +12,9 @@ module.exports = Object.assign({}, common(), {
         path: path.resolve(__dirname, '../../build'),
         libraryTarget: 'umd'
     }
+});
+
+module.exports.module.rules.push({
+    test: /\.wasm$/,
+    loader: "arraybuffer-loader"
 });
diff --git a/packages/perspective/test/js/constructors.js b/packages/perspective/test/js/constructors.js
@@ -44,6 +44,13 @@ var data_3 = [
     {'w': 4.5, 'x': 4, 'y':'d', 'z': false}
 ];
 
+var data_7 = {
+    'w': [1.5, 2.5, 3.5, 4.5],
+    'x': [1, 2, 3, 4],
+    'y': ['a', 'b', 'c', 'd'],
+    'z': [true, false, true, false]
+};
+
 var meta_3 = {
     'w': 'float',
     'x': "integer",
@@ -176,6 +183,13 @@ module.exports = (perspective) => {
             expect(answer).toEqual(result2);
         });
 
+        it("Serializes a simple view to column-oriented JSON", async function () {
+            var table = perspective.table(data_3);
+            var view = table.view({});
+            let result2 = await view.to_columns();
+            expect(data_7).toEqual(result2);
+        });
+
     });
 
     describe("Constructors", function() {