feat: have basic scaling amount input working

1 files changed, 52 insertions, 0 deletions

diff --git a/packages/instant/src/components/scaling_amount_input.tsx b/packages/instant/src/components/scaling_amount_input.tsx
new file mode 100644
index 000000000..a0b7b74af
--- /dev/null
+++ b/packages/instant/src/components/scaling_amount_input.tsx
@@ -0,0 +1,52 @@
+import { BigNumber } from '@0x/utils';
+import * as _ from 'lodash';
+import * as React from 'react';
+
+import { ColorOption } from '../style/theme';
+import { util } from '../util/util';
+
+import { ScalingInput } from './scaling_input';
+import { Container, Text } from './ui';
+
+export interface ScalingAmountInputProps {
+    fontSizePx: number;
+    startWidthCh: number;
+    endWidthCh: number;
+    fontColor?: ColorOption;
+    value?: BigNumber;
+    onChange: (value?: BigNumber, fontSize?: number) => void;
+}
+
+export class ScalingAmountInput extends React.Component<ScalingAmountInputProps> {
+    public static defaultProps = {
+        onChange: util.boundNoop,
+        onFontSizeChange: util.boundNoop,
+    };
+    public render(): React.ReactNode {
+        const { startWidthCh, endWidthCh, fontColor, fontSizePx, value } = this.props;
+        return (
+            <ScalingInput
+                startWidthCh={startWidthCh}
+                endWidthCh={endWidthCh}
+                fontSizePx={fontSizePx}
+                fontColor={fontColor}
+                onChange={this._handleChange}
+                value={!_.isUndefined(value) ? value.toString() : ''}
+                placeholder="0.00"
+            />
+        );
+    }
+    private readonly _handleChange = (event: React.ChangeEvent<HTMLInputElement>, fontSize?: number): void => {
+        const value = event.target.value;
+        let bigNumberValue;
+        if (!_.isEmpty(value)) {
+            try {
+                bigNumberValue = new BigNumber(event.target.value);
+            } catch {
+                // We don't want to allow values that can't be a BigNumber, so don't even call onChange.
+                return;
+            }
+        }
+        this.props.onChange(bigNumberValue, fontSize);
+    };
+}