nsn-comp/es/comps/ellipsis/_util/bisection.js

NSN核心组件

import { NStr } from 'nsn-util';

var bisection = function bisection(props) {
  var targetHeight = props.targetHeight,
      midIndex = props.midIndex,
      beginIndex = props.beginIndex,
      endIndex = props.endIndex,
      text = props.text,
      shadowNode = props.shadowNode,
      tail = props.tail;
  var suffix = tail || '...';
  var begin = beginIndex;
  var mid = midIndex;
  var end = endIndex;

  if (shadowNode) {
    shadowNode.innerHTML = text.substring(0, mid) + suffix;
    var shadowNodeHeight = shadowNode.offsetHeight; //

    if (shadowNodeHeight <= targetHeight) {
      shadowNode.innerHTML = text.substring(0, mid + 1) + suffix;
      shadowNodeHeight = shadowNode.offsetHeight;

      if (shadowNodeHeight > targetHeight || NStr.isEqual(mid, begin)) {
        return mid;
      } //


      begin = mid;

      if (end - begin === 1) {
        mid = 1 + begin;
      } else {
        mid = Math.floor((end - begin) / 2) + begin;
      }

      return bisection({
        targetHeight: targetHeight,
        midIndex: mid,
        beginIndex: begin,
        endIndex: end,
        text: text,
        shadowNode: shadowNode
      });
    } //


    if (mid - 1 < 0) {
      return mid;
    } //


    shadowNode.innerHTML = text.substring(0, mid - 1) + suffix;
    shadowNodeHeight = shadowNode.offsetHeight;

    if (shadowNodeHeight <= targetHeight) {
      return mid - 1;
    }
  } //


  end = mid;
  mid = Math.floor((end - begin) / 2) + begin;
  return bisection({
    targetHeight: targetHeight,
    midIndex: mid,
    beginIndex: begin,
    endIndex: end,
    text: text,
    shadowNode: shadowNode
  });
};

export { bisection };