Allowing to define a default format string per-metric (#750)

caravel/assets/javascripts/modules/caravel.js

@@ -2,6 +2,7 @@ var $ = require('jquery');
 var jQuery = $;
 var d3 = require('d3');
 var Mustache = require('mustache');
+var utils = require('./utils');
 
 // vis sources
 var sourceMap = {
@@ -240,6 +241,12 @@ var px = (function () {
         endpoint += "&force=" + this.force;
         return endpoint;
       },
+      d3format: function (col, number) {
+        // uses the utils memoized d3format function and formats based on
+        // column level defined preferences
+        var format = this.data.column_formats[col];
+        return utils.d3format(format, number);
+      },
       done: function (data) {
         clearInterval(timer);
         token.find("img.loading").hide();

caravel/assets/javascripts/modules/utils.js

@@ -105,9 +105,20 @@ var fixDataTableBodyHeight = function ($tableDom, height) {
       .css('max-height', height - headHeight);
 };
 
+var formatters = {};
+function d3format(format, number) {
+  // Formats a number and memoizes formatters to be reused
+  format = format || '.3s';
+  if (!(format in formatters)) {
+    formatters[format] = d3.format(format);
+  }
+  return formatters[format](number);
+}
+
 module.exports = {
   wrapSvgText: wrapSvgText,
   showModal: showModal,
   toggleCheckbox: toggleCheckbox,
-  fixDataTableBodyHeight: fixDataTableBodyHeight
+  fixDataTableBodyHeight: fixDataTableBodyHeight,
+  d3format: d3format
 };