blocks|key|1607158|text|我们使用一个集合，然后是一个映射。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1607159|通过使用映射来提取，用唯一类型填充该集合。我们包装在[]中给我们一个数组，然后我们重新使用map来重新构建我们的对象。然后，映射重新构建我们的对象，并注意使用filter和map从原始主机数组中获取img值。|offset|length|style|CODE|1607160|​|1607161|let+oldArray=[
++++{type:16,img:['1']},
++++{type:16,img:['2']},
++++{type:16,img:['3']},
++++{type:17,img:['4']}
]

let+newArray+=+[...new+Set(oldArray.map(e+=>+e.type))]
++++++++++++++++.map(e+=>+{
++++++++++++++++++return+{
++++++++++++++++++++type:+e,
++++++++++++++++++++img:+oldArray.filter(i+=>+i.type+===+e).flatMap(x+=>+x.img)
++++++++++++++++++}
++++++++++++++++});
++
console.log(newArray);|code-block|syntax|javascript|1607162|1607163|entityMap^0|0|Q|2|19|3|27|6|2E|3|2R|3|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@$D|T|E|U|F|G]|$D|V|E|W|F|G]|$D|X|E|Y|F|G]|$D|Z|E|10|F|G]|$D|11|E|12|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|13|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|14|8|@]|9|@]|A|$M|N]]|$1|O|3|I|5|6|7|15|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|16|8|@]|9|@]|A|$]]]|Q|$]]

<p>We use a Set and then a map.</p>

<p>The Set is populate with the unique types by using a map to extract. 
We wrap in <code>[]</code> to give us an array the we then re <code>map</code> to build our object back. 
The map then rebuilds our objects and note the use of <code>filter</code> and <code>map</code> to get the <code>img</code> values from the original host array.</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>let oldArray=[
    {type:16,img:['1']},
    {type:16,img:['2']},
    {type:16,img:['3']},
    {type:17,img:['4']}
]

let newArray = [...new Set(oldArray.map(e =&gt; e.type))]
                .map(e =&gt; {
                  return {
                    type: e,
                    img: oldArray.filter(i =&gt; i.type === e).flatMap(x =&gt; x.img)
                  }
                });
  
console.log(newArray);</code></pre>
</div>
</div>
</p>


blocks|key|1607190|text|此解决方案不是reduce，但返回结果与您要查找的结果相同|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1607191|​|1607192|let+oldArray+=+[
++++{type:16,img:['1']},
++++{type:16,img:['2']},
++++{type:16,img:['3']},
++++{type:17,img:['4']}
];

const+transitoryMap+=+new+Map();
for+(const+item+of+oldArray)+{
++++if+(!transitoryMap.has(item.type))+{
++++++++transitoryMap.set(item.type,+[item.img[0]])
++++}+else+{
++++++++const+value+=+transitoryMap.get(item.type)
++++++++value.push(item.img[0])
++++++++transitoryMap.set(item.type,+value)
++++}
}
++++
const+newArray+=+[];
for+(const+item+of+transitoryMap.keys())+{
++++newArray.push({type:item,img:transitoryMap.get(item)})
}

console.log(newArray)|code-block|syntax|javascript|1607193|1607194|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|N|8|@]|9|@]|A|$G|H]]|$1|I|3|C|5|6|7|O|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|K|$]]

<p>This solution is not a reduce but return result you are looking for is the same</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>let oldArray = [
    {type:16,img:['1']},
    {type:16,img:['2']},
    {type:16,img:['3']},
    {type:17,img:['4']}
];

const transitoryMap = new Map();
for (const item of oldArray) {
    if (!transitoryMap.has(item.type)) {
        transitoryMap.set(item.type, [item.img[0]])
    } else {
        const value = transitoryMap.get(item.type)
        value.push(item.img[0])
        transitoryMap.set(item.type, value)
    }
}
    
const newArray = [];
for (const item of transitoryMap.keys()) {
    newArray.push({type:item,img:transitoryMap.get(item)})
}

console.log(newArray)</code></pre>
</div>
</div>
</p>


blocks|key|1821819|text|下面是一个使用reduce的示例。我添加了一个tracker来跟踪newArray中的类型。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1821820|let+oldArray+=+[
++++{type:16,img:['1']},
++++{type:16,img:['2']},
++++{type:16,img:['3']},
++++{type:17,img:['4']}
];

oldArray.reduce((a,c)=>{
++++let+index+=+a.tracker.indexOf(c.type);
++++if(index+===+-1)+{
++++++++a.tracker.push(c.type);
++++++++a.newArray.push({...c,+img:[...c.img]});
++++}+else+{
++++++++a.newArray[index].img.push(...c.img);
++++}
++++return+a;
},{tracker:[],newArray:[]}).newArray;|code-block|syntax|javascript|1821821|entityMap^0|7|6|N|7|X|8|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|U|8|@]|D|@]|E|$]]]|L|$]]

<p>Here is an example using <code>reduce</code>. I have added a <code>tracker</code> to keep track of type in the <code>newArray</code>.</p>

<pre class="lang-js prettyprint-override"><code>let oldArray = [
    {type:16,img:['1']},
    {type:16,img:['2']},
    {type:16,img:['3']},
    {type:17,img:['4']}
];

oldArray.reduce((a,c)=&gt;{
    let index = a.tracker.indexOf(c.type);
    if(index === -1) {
        a.tracker.push(c.type);
        a.newArray.push({...c, img:[...c.img]});
    } else {
        a.newArray[index].img.push(...c.img);
    }
    return a;
},{tracker:[],newArray:[]}).newArray;
</code></pre>


blocks|key|1821823|text|您可以使用reduce|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1821824|​|1821825|let+oldArray+=+[{type:+16,img:+['1']},{type:+16,img:+['2']},{type:+16,img:+['3']},{type:+17,img:+['4']}];

let+newArray+=+oldArray.reduce((acc,+curr)+=>+{
++acc.some(({
++++type
++})+=>+type+==+curr.type)+?+acc.find(({
++++type
++})+=>+type+==+curr.type).img.push(curr.img[0])+:+acc.push(curr);
++return+acc;
},+[]);

console.log(newArray);|code-block|syntax|javascript|1821826|1821827|entityMap^0|5|6|0|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|T|8|@]|D|@]|E|$K|L]]|$1|M|3|G|5|6|7|U|8|@]|D|@]|E|$]]|$1|N|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|O|$]]

<p>You can use <code>reduce</code>:</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="false" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>let oldArray = [{type: 16,img: ['1']},{type: 16,img: ['2']},{type: 16,img: ['3']},{type: 17,img: ['4']}];

let newArray = oldArray.reduce((acc, curr) =&gt; {
  acc.some(({
    type
  }) =&gt; type == curr.type) ? acc.find(({
    type
  }) =&gt; type == curr.type).img.push(curr.img[0]) : acc.push(curr);
  return acc;
}, []);

console.log(newArray);</code></pre>
</div>
</div>
</p>


<p>I have an array like this</p>

<pre><code>let oldArray=[
    {type:16,img:['1']},
    {type:16,img:['2']},
    {type:16,img:['3']},
    {type:17,img:['4']}
]
</code></pre>

<p>if the type is the same, i want to concat the value.
The result I want is:</p>

<pre><code>let newArray=[
    {type:16,img:['1','2','3']},
    {type:17,img:['4']}
]
</code></pre>

<p>I tried to used reduce function:</p>

<pre><code>    oldArray.reduce((acc,cur,idx,src)=&gt;{
if(cur.type===a[idx+1].type){
    cur.img.concat(a[idx+1].img);
    acc.push(cur)
} else {
    acc.push(a[idx+1])
}
    return acc

},[])
</code></pre>

<p>It seems that there is an error
Can anyone help? Thanks.</p>

<hr>

<p>Alternative to Bibberty's solution:flatMap is much clearer than reduce</p>

<pre><code>let newArray = [...new Set(oldArray.map(e =&gt; e.type))]
                                    .map(e =&gt; {
                                        return {
                                            type: e,
                                            img: (oldArray.filter(i =&gt; i.type === e).map(x =&gt; x.img)).reduce((acc,cur,idx,src)=&gt;{
                                                let length=src.length
                                                let tep=cur.concat(src[idx+1]);
                                                src[idx+1]=tep


                                                return src[idx=length-1]
                                            },[])
                                        }
                                    });

    console.log(newArray);
</code></pre>


How to reduce an array with duplicate value?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有一个这样的数组let oldArray=[    {type:16,img:['1']},    {type:16,img:['2']},    {type:16,img:['3']},    {type:17,img:['4']}]如果类型相同，我希望将值连接起来。我想要的结果是：let newArray=[  ...

问如何减少重复值的数组？
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问如何减少重复值的数组？
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