设置和删除cookie

//设置
const date = new Date();
date.setTime(date.getTime() + 24 * 60 * 60 * 1000);
const lastTime = date.toGMTString();
document.cookie = `api_token=${res.data.api_token};expires=${lastTime};`;
document.cookie = `identity_token=${res.data.identity_token};expires=${lastTime};`;
// 删除 => 只需设置失效时间为过去的时间，就会自动被删除
const iden=document.cookie.indexOf("identity_token=");
if(iden == -1){
    return;
} else{
    const date = new Date();
    date.setTime(date.getTime() - 24 * 60 * 60 * 1000);
    const lastTime = date.toGMTString();
    document.cookie = `identity_token='';expires=${lastTime};`;
}