第七天：把js简单化
<h5>js有时候被我们想象的太复杂了</h5>
<h5>思路：记住你用到的简单思路</h5>
<ol>
<li>
<p>数组去重(使用 Set 删除重复项)</p>
<pre><code>//数组去重
function removeDuplicates(arr){
return [...new Set(arr)];
}</code></pre>
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<li>
<p><strong>reduce</strong>(function(accumulator,currentValue,currentIndex,array))
元素值相加：</p>
<ul>
<li>accumulator 累计器</li>
<li>currentValue 当前值</li>
<li>currentIndex 当前索引</li>
<li>array 数组</li>
</ul>
<p>let users = [{
name: 'Yazeed',
age: 25
}, {
name: 'Sam',
age: 30
}, {
name: 'Bill',
age: 20
}];
let totalAge = users.reduce((total,user) => total+user.age,0)
console.log(totalAge) //75</p>
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</ol>
<p>3.Map的相关功能</p>
<ul>
<li>currentValue元素的当前值</li>
<li>index 索引</li>
<li>array 数组</li>
<li>
<p>thisArg 执行callback使用的this的值</p>
<p>users = [{
name: 'Yazeed',
age: 25
}, {
name: 'Sam',
age: 30
}, {
name: 'Bill',
age: 20
}];
let usernames = users.map((user) => user.name);
console.log(usernames); // ["Yazeed", "Sam", "Bill"]</p>
</li>
</ul>