flow like the river

VISUALIZACION/node_modules/d3-format/src/formatGroup.js

@@ -0,0 +1,18 @@
+export default function(grouping, thousands) {
+  return function(value, width) {
+    var i = value.length,
+        t = [],
+        j = 0,
+        g = grouping[0],
+        length = 0;
+
+    while (i > 0 && g > 0) {
+      if (length + g + 1 > width) g = Math.max(1, width - length);
+      t.push(value.substring(i -= g, i + g));
+      if ((length += g + 1) > width) break;
+      g = grouping[j = (j + 1) % grouping.length];
+    }
+
+    return t.reverse().join(thousands);
+  };
+}