Merge pull request #1587 from KapJI/slider-perf

[Slider] tiny performance improvement, code refactoring.
mui · Sep 29, 2015 · 4dcdae9 · 4dcdae9
2 parents fc0713e + 4ec0543
commit 4dcdae9
Showing 1 changed file with 4 additions and 26 deletions.
diff --git a/src/slider.jsx b/src/slider.jsx
@@ -346,36 +346,17 @@ const Slider = React.createClass({
 
  _alignValue(val) {
  let { step, min } = this.props;
-
- let valModStep = (val - min) % step;
- let alignValue = val - valModStep;
-
- if (Math.abs(valModStep) * 2 >= step) {
- alignValue += (valModStep > 0) ? step : (-step);
- }
-
+ let alignValue = Math.round((val - min) / step) * step + min;
  return parseFloat(alignValue.toFixed(5));
  },
 
  _constrain() {
  let { min, max, step } = this.props;
+ let steps = (max - min) / step;
  return (pos) => {
  let pixelMax = React.findDOMNode(this.refs.track).clientWidth;
- let pixelStep = pixelMax / ((max - min) / step);
-
- let cursor = min;
- let i;
- for (i = 0; i < (max - min) / step; i++) {
- let distance = (pos.left - cursor);
- let nextDistance = (cursor + pixelStep) - pos.left;
- if (Math.abs(distance) > Math.abs(nextDistance)) {
- cursor += pixelStep;
- }
- else {
- break;
- }
- }
-
+ let pixelStep = pixelMax / steps;
+ let cursor = Math.round(pos.left / pixelStep) * pixelStep;
  return {
  left: cursor,
  };
@@ -442,9 +423,6 @@ const Slider = React.createClass({
  _dragX(e, pos) {
  let max = React.findDOMNode(this.refs.track).clientWidth;
  if (pos < 0) pos = 0; else if (pos > max) pos = max;
- if (pos === this.props.min) {
- return this._updateWithChangeEvent(e, 0);
- }
  this._updateWithChangeEvent(e, pos / max);
  },