missing formatValue.js

react/src/util/formatValue.js

@@ -0,0 +1,49 @@
+// ref: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Math/round#Decimal_rounding
+export function formatValue(formatType, formatValue, formatExp) {
+  /**
+   * Decimal adjustment of a number.
+   *
+   * @param {String}  type  The type of adjustment.
+   * @param {Number}  value The number.
+   * @param {Integer} exp   The exponent (the 10 logarithm of the adjustment base).
+   * @returns {Number} The adjusted value.
+   */
+  function decimalAdjust(type, value, exp) {
+    // If the exp is undefined or zero...
+    if (typeof exp === 'undefined' || +exp === 0) {
+      return Math[type](value);
+    }
+    value = +value;
+    exp = +exp;
+    // If the value is not a number or the exp is not an integer...
+    if (isNaN(value) || !(typeof exp === 'number' && exp % 1 === 0)) {
+      return NaN;
+    }
+    // If the value is negative...
+    if (value < 0) {
+      return -decimalAdjust(type, -value, exp);
+    }
+    // Shift
+    value = value.toString().split('e');
+    value = Math[type](+(value[0] + 'e' + (value[1] ? (+value[1] - exp) : -exp)));
+    // Shift back
+    value = value.toString().split('e');
+    return +(value[0] + 'e' + (value[1] ? (+value[1] + exp) : exp));
+  }
+
+  if (formatValue >= 1) {
+    formatExp = -3;
+  }
+
+  switch (formatType) {
+    case 'round':
+      return decimalAdjust('round', formatValue, formatExp);
+      break;
+    case 'floor':
+      return decimalAdjust('floor', formatValue, formatExp);
+      break;
+    case 'ceil':
+      return decimalAdjust('ceil', formatValue, formatExp);
+      break;
+  }
+}