diff --git a/superset/assets/javascripts/chart/Chart.jsx b/superset/assets/javascripts/chart/Chart.jsx
index 958d353f95540..bd7e4f80c2b7b 100644
--- a/superset/assets/javascripts/chart/Chart.jsx
+++ b/superset/assets/javascripts/chart/Chart.jsx
@@ -8,6 +8,7 @@ import ChartBody from './ChartBody';
 import Loading from '../components/Loading';
 import StackTraceMessage from '../components/StackTraceMessage';
 import visMap from '../../visualizations/main';
+import sandboxedEval from '../modules/sandbox';
 
 const propTypes = {
   annotationData: PropTypes.object,
@@ -141,8 +142,15 @@ class Chart extends React.PureComponent {
 
   renderViz() {
     const viz = visMap[this.props.vizType];
+    const fd = this.props.formData;
+    const qr = this.props.queryResponse;
     try {
-      viz(this, this.props.queryResponse, this.props.setControlValue);
+      // Executing user-defined data mutator function
+      if (fd.js_data) {
+        qr.data = sandboxedEval(fd.js_data)(qr.data);
+      }
+      // [re]rendering the visualization
+      viz(this, qr, this.props.setControlValue);
     } catch (e) {
       this.props.actions.chartRenderingFailed(e, this.props.chartKey);
     }
diff --git a/superset/assets/javascripts/explore/components/controls/TextAreaControl.jsx b/superset/assets/javascripts/explore/components/controls/TextAreaControl.jsx
index 47b5454f4ccd5..3e968546a5a3b 100644
--- a/superset/assets/javascripts/explore/components/controls/TextAreaControl.jsx
+++ b/superset/assets/javascripts/explore/components/controls/TextAreaControl.jsx
@@ -7,6 +7,7 @@ import 'brace/mode/sql';
 import 'brace/mode/json';
 import 'brace/mode/html';
 import 'brace/mode/markdown';
+import 'brace/mode/javascript';
 
 import 'brace/theme/textmate';
 
@@ -16,24 +17,21 @@ import { t } from '../../../locales';
 
 const propTypes = {
   name: PropTypes.string.isRequired,
-  label: PropTypes.string,
-  description: PropTypes.string,
   onChange: PropTypes.func,
   value: PropTypes.string,
   height: PropTypes.number,
-  language: PropTypes.oneOf([null, 'json', 'html', 'sql', 'markdown']),
   minLines: PropTypes.number,
   maxLines: PropTypes.number,
   offerEditInModal: PropTypes.bool,
+  language: PropTypes.oneOf([null, 'json', 'html', 'sql', 'markdown', 'javascript']),
+  aboveEditorSection: PropTypes.node,
 };
 
 const defaultProps = {
-  label: null,
-  description: null,
   onChange: () => {},
   value: '',
   height: 250,
-  minLines: 10,
+  minLines: 3,
   maxLines: 10,
   offerEditInModal: true,
 };
@@ -73,6 +71,14 @@ export default class TextAreaControl extends React.Component {
         />
       </FormGroup>);
   }
+  renderModalBody() {
+    return (
+      <div>
+        <div>{this.props.aboveEditorSection}</div>
+        {this.renderEditor(true)}
+      </div>
+    );
+  }
   render() {
     const controlHeader = <ControlHeader {...this.props} />;
     return (
@@ -88,7 +94,7 @@ export default class TextAreaControl extends React.Component {
                 {t('Edit')} <strong>{this.props.language}</strong> {t('in modal')}
               </Button>
             }
-            modalBody={this.renderEditor(true)}
+            modalBody={this.renderModalBody(true)}
           />}
       </div>
     );
diff --git a/superset/assets/javascripts/explore/stores/controls.jsx b/superset/assets/javascripts/explore/stores/controls.jsx
index 7117712d2100e..95d4813f15af8 100644
--- a/superset/assets/javascripts/explore/stores/controls.jsx
+++ b/superset/assets/javascripts/explore/stores/controls.jsx
@@ -46,6 +46,15 @@ const sortAxisChoices = [
   ['value_desc', 'sum(value) descending'],
 ];
 
+const sandboxUrl = 'https://github.com/apache/incubator-superset/blob/master/superset/assets/javascripts/modules/sandbox.js';
+const sandboxedEvalInfo = (
+  <span>
+    {t('While this runs in a ')}
+    <a href="https://nodejs.org/api/vm.html#vm_script_runinnewcontext_sandbox_options">sandboxed vm</a>
+    , {t('a set of')}<a href={sandboxUrl}> useful objects are in context </a>
+    {t('to be used where necessary.')}
+  </span>);
+
 const groupByControl = {
   type: 'SelectControl',
   multi: true,
@@ -1759,5 +1768,18 @@ export const controls = {
     default: false,
   },
 
+  js_data: {
+    type: 'TextAreaControl',
+    label: t('Javascript data mutator'),
+    description: t('Define a function that receives intercepts the data objects and can mutate it'),
+    language: 'javascript',
+    default: '',
+    height: 100,
+    aboveEditorSection: (
+      <p>
+        Define a function that intercepts the <code>data</code> object passed to the visualization
+        and returns a similarly shaped object. {sandboxedEvalInfo}
+      </p>),
+  },
 };
 export default controls;
diff --git a/superset/assets/javascripts/explore/stores/visTypes.js b/superset/assets/javascripts/explore/stores/visTypes.js
index 2c5f2a61e1889..88f6710a9daff 100644
--- a/superset/assets/javascripts/explore/stores/visTypes.js
+++ b/superset/assets/javascripts/explore/stores/visTypes.js
@@ -607,6 +607,7 @@ export const visTypes = {
     controlPanelSections: [
       {
         label: t('Code'),
+        expanded: true,
         controlSetRows: [
           ['markup_type'],
           ['code'],
diff --git a/superset/assets/javascripts/modules/sandbox.js b/superset/assets/javascripts/modules/sandbox.js
new file mode 100644
index 0000000000000..24473adb3d644
--- /dev/null
+++ b/superset/assets/javascripts/modules/sandbox.js
@@ -0,0 +1,25 @@
+// A safe alternative to JS's eval
+import vm from 'vm';
+import _ from 'underscore';
+
+// Objects exposed here should be treated like a public API
+// if `underscore` had backwards incompatible changes in a future release, we'd
+// have to be careful about bumping the library as those changes could break user charts
+const GLOBAL_CONTEXT = {
+  console,
+  _,
+};
+
+// Copied/modified from https://github.com/hacksparrow/safe-eval/blob/master/index.js
+export default function sandboxedEval(code, context, opts) {
+  const sandbox = {};
+  const resultKey = 'SAFE_EVAL_' + Math.floor(Math.random() * 1000000);
+  sandbox[resultKey] = {};
+  const codeToEval = resultKey + '=' + code;
+  const sandboxContext = { ...GLOBAL_CONTEXT, ...context };
+  Object.keys(sandboxContext).forEach(function (key) {
+    sandbox[key] = sandboxContext[key];
+  });
+  vm.runInNewContext(codeToEval, sandbox, opts);
+  return sandbox[resultKey];
+}
diff --git a/superset/assets/spec/javascripts/modules/sandbox_spec.jsx b/superset/assets/spec/javascripts/modules/sandbox_spec.jsx
new file mode 100644
index 0000000000000..85b36472fca65
--- /dev/null
+++ b/superset/assets/spec/javascripts/modules/sandbox_spec.jsx
@@ -0,0 +1,17 @@
+import { it, describe } from 'mocha';
+import { expect } from 'chai';
+
+import sandboxedEval from '../../../javascripts/modules/sandbox';
+
+describe('sandboxedEval', () => {
+  it('works like a basic eval', () => {
+    expect(sandboxedEval('100')).to.equal(100);
+    expect(sandboxedEval('v => v * 2')(5)).to.equal(10);
+  });
+  it('d3 is in context and works', () => {
+    expect(sandboxedEval("l => _.find(l, s => s === 'bar')")(['foo', 'bar'])).to.equal('bar');
+  });
+  it('passes context as expected', () => {
+    expect(sandboxedEval('foo', { foo: 'bar' })).to.equal('bar');
+  });
+});