scroolToIndex of tools

Most left navigation scroll achieve sub-element to the parent element: Positioning demand

Solution: Find offsetLeft value of the child element, and then let the parent element rolling offsetLeft, parenDom.scrollLeft = childDom.offsetLeft

ScrollToIndex function defined on the prototype vue

 prototype.js

/ * * 
 * Scroll to the index 
 * @param {Option = 
 * // parent element parentsDom DOM 
 * childDom // child element DOM 
 *} 
 * / 
Vue.prototype.scrollToIndex = function (Options = {}) { 
  the let width = 0 ; 
  found in the global // 

  const EL = document.getElementsByClassName (options.parentsDom), 
    Defaults = the setDefault (Options), 
    elChild = document.getElementsByClassName (options.childDom); 

  IF (! judgeOptions (Defaults)) {
     return ; 
  } 
  IF  (Defaults .x) {
    width= elChild[0].offsetLeft;
  }
  scrollLeft(el, width);
};

function setDefault(options) {
  const defaults = {
    parentsDom: '',
    childDom: '',
    x: true,
    y: false,
  };
  return Object.assign({}, defaults, options);
}

function judgeOptions(options) {
  console.log(options, 'options');
  if (typeof options.parentsDom !== 'string' || typeof options.childDom !== 'string'
    || document.getElementsByClassName(options.parentsDom).length === 0
    || document.getElementsByClassName(options.childDom).length === 0
  ) {
    console.warn('Dom必须传是className并且存在');
    return false;
  }
  return true;
}

function scrollLeft(el = '', width = 0) {
  if (!el) {
    return;
  }
  el[0].scrollLeft = width;
}

 .view

this.scrollToIndex({
    parentsDom: 'J-nav-select',
    childDom: 'J-nav-active',
});