承接上文，这是第7个案例，这个案例没什么说的，主要有三个注意点：

附上项目链接: 

// 1. slice(begin, end) 如果end被省略，则slice会一直提取到原数组末尾。如果end大于数组长度，slice也会一直提取到原数组末尾。// 2. {isAdult},直接创建了一个对象,他的key是isAdult,value是isAdult的值// 3. new Date()).getFullYear()),我自己写的时候是直接写了2019去计算,还没形成看到日期就用日期方法的条件反射

const people = [      { name: 'Wes', year: 1988 },      { name: 'Kait', year: 1986 },      { name: 'Irv', year: 1970 },      { name: 'Lux', year: 2015 }    ];    const comments = [      { text: 'Love this!', id: 523423 },      { text: 'Super good', id: 823423 },      { text: 'You are the best', id: 2039842 },      { text: 'Ramen is my fav food ever', id: 123523 },      { text: 'Nice Nice Nice!', id: 542328 }    ];    // Some and Every Checks    // Array.prototype.some() // is at least one person 19?    // const isAdult = people.some(function(person) {
        //   const currentYear = (new Date()).getFullYear();    //   if(currentYear - person.year >= 19) {
        //     return true;    //   }    // });    const isAdult = people.some(person => ((new Date()).getFullYear()) - person.year >= 19);    console.log({isAdult});    // Array.prototype.every() // is everyone 19?    const allAdults = people.every(person => ((new Date()).getFullYear()) - person.year >= 19);    console.log({allAdults});    // Array.prototype.find()    // Find is like filter, but instead returns just the one you are looking for    // find the comment with the ID of 823423    const comment = comments.find(comment => comment.id === 823423);    console.log(comment);    // Array.prototype.findIndex()    // Find the comment with this ID    // delete the comment with the ID of 823423    const index = comments.findIndex(comment => comment.id === 823423);    console.log(index);    // comments.splice(index, 1);    const newComments = [        ...comments.slice(0, index),        ...comments.slice(index + 1)    ];