fix(Table): constructor asserts param types (#522)

addon/classes/Table.js

@@ -1,4 +1,5 @@
 import { A as emberArray } from '@ember/array';
+import { assert } from '@ember/debug';
 import EmberObject, { computed, get } from '@ember/object';
 import Row from 'ember-light-table/classes/Row';
 import Column from 'ember-light-table/classes/Column';
@@ -148,6 +149,9 @@ export default class Table extends EmberObject.extend({
   constructor(columns = [], rows = [], options = {}) {
     super();
 
+    assert('[ember-light-table] columns must be an array if defined', columns instanceof Array);
+    assert('[ember-light-table] rows must be an array if defined', rows instanceof Array);
+
     let _options = mergeOptionsWithGlobals(options);
     let _columns = emberArray(Table.createColumns(columns));
     let _rows = emberArray(Table.createRows(rows, _options.rowOptions));

tests/unit/classes/table-test.js

@@ -23,6 +23,17 @@ test('create table - with options', function(assert) {
   assert.ok(table.columns[0] instanceof Column);
 });
 
+test('create table - invalid constructor', function(assert) {
+  assert.expect(2);
+
+  assert.throws(() => {
+    new Table([{}, {}], null);
+  }, /\[ember-light-table] rows must be an array if defined/, 'rows is not an array');
+  assert.throws(() => {
+    new Table(null, [{}]);
+  }, /\[ember-light-table] columns must be an array if defined/, 'columns is not an array');
+});
+
 test('reopen table', function(assert) {
   assert.equal(typeof Table.reopen, 'function', 'reopen is a function');
   assert.equal(typeof Table.reopenClass, 'function', 'reopenClass is a function');