implement smart number format

packages/superset-ui-number-format/src/factories/createSmartNumberFormatter.ts

@@ -0,0 +1,46 @@
+import { format as d3Format } from 'd3-format';
+import NumberFormatter from '../NumberFormatter';
+
+export default function createSmartNumberFormatter(
+  config: {
+    description?: string;
+    signed?: boolean;
+    id?: string;
+    label?: string;
+  } = {},
+) {
+  const { description, signed = false, id, label } = config;
+  const siFormatter = d3Format(`.3~s`);
+  const float2PointFormatter = d3Format(`.2~f`);
+  const float3PointFormatter = d3Format(`.3~f`);
+
+  const getSign = signed ? () => '' : (value: number) => (value > 0 ? '+' : '');
+
+  function formatValue(value: number) {
+    if (value === 0) {
+      return '0';
+    } else {
+      const absoluteValue = Math.abs(value);
+      if (absoluteValue >= 1000) {
+        // Normal human being are more familiar
+        // with billion (B) that giga (G)
+        return siFormatter(value).replace('G', 'B');
+      } else if (absoluteValue >= 1) {
+        return float2PointFormatter(value);
+      } else if (absoluteValue >= 0.001) {
+        return float3PointFormatter(value);
+      } else if (absoluteValue > 0.000001) {
+        return `${siFormatter(value * 100000)}µ`;
+      }
+
+      return siFormatter(value);
+    }
+  }
+
+  return new NumberFormatter({
+    description,
+    formatFunc: value => `${getSign(value)}${formatValue(value)}`,
+    id: id || `smart_number${signed ? '_change' : ''}`,
+    label: label || 'Adaptive formatter',
+  });
+}