[explore] adding y_axis_bounds to force Y axis bounds (#2878)

* [explore] adding y_axis_bounds to force Y axis

* Handling comments

superset/assets/javascripts/explore/components/controls/BoundsControl.jsx

@@ -0,0 +1,95 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+import { Col, Row, FormGroup, FormControl } from 'react-bootstrap';
+import ControlHeader from '../ControlHeader';
+
+const propTypes = {
+  name: PropTypes.string.isRequired,
+  label: PropTypes.string,
+  description: PropTypes.string,
+  onChange: PropTypes.func,
+  value: PropTypes.array,
+};
+
+const defaultProps = {
+  label: null,
+  description: null,
+  onChange: () => {},
+  value: [null, null],
+};
+
+export default class BoundsControl extends React.Component {
+  constructor(props) {
+    super(props);
+    this.state = {
+      minMax: [
+        props.value[0] === null ? '' : props.value[0],
+        props.value[1] === null ? '' : props.value[1],
+      ],
+    };
+    this.onChange = this.onChange.bind(this);
+    this.onMinChange = this.onMinChange.bind(this);
+    this.onMaxChange = this.onMaxChange.bind(this);
+  }
+  onMinChange(event) {
+    this.setState({
+      minMax: [
+        event.target.value,
+        this.state.minMax[1],
+      ],
+    }, this.onChange);
+  }
+  onMaxChange(event) {
+    this.setState({
+      minMax: [
+        this.state.minMax[0],
+        event.target.value,
+      ],
+    }, this.onChange);
+  }
+  onChange() {
+    const mm = this.state.minMax;
+    const errors = [];
+    if (mm[0] && isNaN(mm[0])) {
+      errors.push('`Min` value should be numeric or empty');
+    }
+    if (mm[1] && isNaN(mm[1])) {
+      errors.push('`Max` value should be numeric or empty');
+    }
+    if (errors.length === 0) {
+      this.props.onChange([parseFloat(mm[0]), parseFloat(mm[1])], errors);
+    } else {
+      this.props.onChange([null, null], errors);
+    }
+  }
+  render() {
+    return (
+      <div>
+        <ControlHeader {...this.props} />
+        <FormGroup bsSize="small">
+          <Row>
+            <Col xs={6}>
+              <FormControl
+                type="text"
+                placeholder="Min"
+                onChange={this.onMinChange}
+                value={this.state.minMax[0]}
+              />
+            </Col>
+            <Col xs={6}>
+              <FormControl
+                type="text"
+                placeholder="Max"
+                onChange={this.onMaxChange}
+                value={this.state.minMax[1]}
+              />
+            </Col>
+          </Row>
+        </FormGroup>
+      </div>
+    );
+  }
+}
+
+BoundsControl.propTypes = propTypes;
+BoundsControl.defaultProps = defaultProps;