vue查找组件

1、由一个组件，向上找到最近的指定组件

/**
 * context 当前组件，componentName 需要查找的组件名称
 */
function findComponentUpward (context, componentName) {
  let parent = context.$parent;
  let name = parent.$options.name;
  while (parent && (!name || [componentName].indexOf(name) < 0)) {
    parent = parent.$parent;
    if (parent) name = parent.$options.name;
  }
  return parent;
}

2、由一个组件，向上找到所有的指定组件

function findComponentsUpward (context, componentName) {
  let parents = [];
  const parent = context.$parent;
  if (parent) {
    if (parent.$options.name === componentName) parents.push(parent);
    return parents.concat(findComponentsUpward(parent, componentName));
  } else {
    return [];
  }
}

3、由一个组件，向下找到最近的指定组件

function findComponentDownward (context, componentName) {
  const childrens = context.$children;
  let children = null;
  if (childrens.length) {
    for (const child of childrens) {
      const name = child.$options.name;
      if (name === componentName) {
        children = child;
        break;
      } else {
        children = findComponentDownward(child, componentName);
        if (children) break;
      }
    }
  }
  return children;
}

4、由一个组件，向下找到所有指定的组件

function findComponentsDownward (context, componentName) {
  return context.$children.reduce((components, child) => {
    if (child.$options.name === componentName) components.push(child);
    const foundChilds = findComponentsDownward(child, componentName);
    return components.concat(foundChilds);
  }, []);
}

5、由一个组件，找到指定组件的兄弟组件

function findBrothersComponents (context, componentName, exceptMe = true) {
  let res = context.$parent.$children.filter(item => {
    return item.$options.name === componentName;
  });
  let index = res.findIndex(item => item._uid === context._uid);
  if (exceptMe) res.splice(index, 1);
  return res;
}