四种情况：

1. 无模式
2. s*
3. .*
4. .

    export default (str, pattern) => {
      /**
     * 如何分组？
     * split？
     *    1.如何用于分组的断点不被刨除。
     *    2.断点进行分组
     * match？
     *    1.将字符串完全匹配
     *    2.需要分组的部分使用排他性的组合
     */
      const modeArr = pattern.match(/([a-z.]\*)|(\.)|([a-z]+(?=([a-z.]\*)|$))/g)
      // const modeArr = pattern.split(/([a-z.]\*)|(\.)|([a-z]+(?=([a-z.]\*)|$))/g).filter(item => !!item)
      let rest = str
      for (let i = 0, length = modeArr.length; i < length; i++) {
        const mode = modeArr[i]
        if (mode.indexOf('.') !== -1 || mode.indexOf('*') !== -1) {
          if (mode === '.') {
            rest = rest.slice(1)
          } else if (mode === '.*') {
            rest = rest.slice(rest.match(new RegExp(`${rest.charAt(0)}*`))[0].length)
          } else {
            if (rest.charAt(0) === mode[0]) {
              rest = rest.slice(rest.match(new RegExp(`${rest.charAt(0)}*`))[0].length)
            } else {
              return false
            }
          }
        } else {
          if (rest.slice(0, mode.length) === mode) {
            rest = rest.slice(mode.length)
          } else {
            return false
          }
        }
      }
      if (rest) {
        return false
      }
      return true
    }

测试用例

import regModeStr from '../../code/regexp/lesson2'

test('regModeStr', () => {
  expect(regModeStr('aaa', 'caa*')).toBe(false)
})
test('regModeStr:2', () => {
  expect(regModeStr('aaabc', 'a*bc')).toBe(true)
})
test('regModeStr:3', () => {
  expect(regModeStr('aaabc', 'a*.*')).toBe(false)
})

test('regModeStr:4', () => {
  expect(regModeStr('aa', '.a')).toBe(true)
})

test('regModeStr:5', () => {
  expect(regModeStr('aab', '.*')).toBe(false)
})