js设计模式问题

Question

export const typeMarry = (type) => {  const charts = ['pie','bar','line'],        text = ['normalText','multText'],        media = ['file','picture','music','video']  if(charts.indexOf(type) !== -1) {    return 'CHARTS'  }  if(text.indexOf(type) !== -1) {    return 'TEXT'  }  if(media.indexOf(type) !== -1) {    return 'MEDIA'  }}这个方法如何改写成维护性高写法，类似于策略模式？

Answer 1

扩展的话只用修改types就行了

const types = {

  'CHARTS':['pie','bar','line'],

  'TEXT':['normalText','multText'],

  'MEDIA':['file','picture','music','video'],

}

export const typeMarry = (type) => {

   for(var k in types)

     if(types[k].includes(type))

       return k;

}

Answer 2

function isCharts (type) {

  return ['pie','bar','line'].includes(type) ? 'CHARTS' : false

}

function isText (type) {

  return ['normalText','multText'].includes(type) ? 'TEXT' : false

}

function isMedia (type) {

  return ['file','picture','music','video'].includes(type) ? 'MEDIA' : false

}

const typefun = [isCharts, isText, isMedia]

export const typeMarry = (type) => {

  for (let i = 0, len = typefun.length; i < len; i++) {

    let cur = typefun[i](type)

    if (cur) return cur

  }

}

Answer 3

直接返回组件实例就行了，没有更多代码的话也没什么好优化的点。