目前想到的方法有这么几个
1.indexOf() -> ES5
const array = [\'apple\', \'banance\', \'orange\']
array.indexOf(\'apple\') // 0 存在
array.indexOf(\'strawBerry\') // -1不存在
2.find() -> ES6
const array = [\'apple\', \'banance\', \'orange\']
array.find(obj => obj == \'banance\') //banance 存在
array.find(obj => obj == \'strawBally\') //undefined 不存在
const arrayList = [
{name: \'张三\'}， {name: \'李四\'}
]
arrayList.find(obj => obj.name == \'李四\') //{name: \'李四\'} 存在
arrayList.find(obj => obj.name == \'王五\') //undefined 不存在
3.findIndex() -> ES6
const array = [\'apple\', \'banance\', \'orange\']
array.findIndex(obj => obj == \'banance\') //大于0存在
array.findIndex(obj => obj == \'strawBally\') //-1 不存在
3.includes()
const array = [\'apple\', \'banance\', \'orange\']
array.includes(\'banance\') //true存在
array.includes(\'strawBally\') //false存在
4.filter()
const array = [\'apple\', \'banance\', \'orange\']
array.filter(obj => obj == \'orange\') //[\'orange\'] 存在
array.filter(obj => obj == \'strawBally\') //[] 不存在
const array = [{ name: \'banance\' }, { name: \'apple\' }]
console.log(array.filter(obj => obj.name === \'apple\')) //[{name: \'apple\'}] 存在
console.log(array.filter(obj => obj.name === \'strawBally\')) //[] 不存在