blocks|key|997551|text|您可以使用typeof检查key是否存在。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|997552|if+(typeof+obj[0][val]+!==+"undefined"+)+{
++++console.log('exists');
}+else+{
++++console.log('does+not+exist');
}|code-block|syntax|javascript|997553|注意:有索引0，因为您正在检查的对象是数组obj的元素0。|997554|这里有一把小提琴：|997555|​|997556|var+obj+=+[{
		"7364234":"hsjd",
		"tom+and+jerry":"dsjdas",
		"mickey+mouse":"kfjskdsad",
		"popeye+the+sailor+man":"alkdsajd",
		"the+carribean":"kasjdsjad"
	}];

	if+(+typeof+obj[0]["the+carribean"]+!==+'undefined'+)+{
		console.log('exists');
	}+else+{
		console.log('does+not+exist');
	}|997557|997558|如下所示，您也可以使用obj[0][val]+===+undefined|997559|您还可以：|997560|var+obj+=+[{
++++"7364234":"hsjd",
++++"tom+and+jerry":"dsjdas",
++++"mickey+mouse":"kfjskdsad",
++++"popeye+the+sailor+man":"alkdsajd",
++++"the+carribean":"kasjdsjad"
}];

var+val+=+"7364234";

if+(+val+in+obj[0]+)+{
++++console.log('exists');
}+else+{
++++console.log('does+not+exist');
}|997561|entityMap^0|5|6|D|3|0|0|6|1|L|3|0|0|0|0|0|B|P|0|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@$9|12|A|13|B|C]|$9|14|A|15|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|17|8|@$9|18|A|19|B|C]|$9|1A|A|1B|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|1C|8|@]|D|@]|E|$]]|$1|O|3|P|5|6|7|1D|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1E|8|@]|D|@]|E|$I|J]]|$1|S|3|P|5|6|7|1F|8|@]|D|@]|E|$]]|$1|T|3|U|5|6|7|1G|8|@$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|V|3|W|5|6|7|1J|8|@]|D|@]|E|$]]|$1|X|3|Y|5|H|7|1K|8|@]|D|@]|E|$I|J]]|$1|Z|3|-4|5|6|7|1L|8|@]|D|@]|E|$]]]|10|$]]

<p>you can use <code>typeof</code> to check if <code>key</code> exist</p>

<pre><code>if (typeof obj[0][val] !== "undefined" ) {
    console.log('exists');
} else {
    console.log('does not exist');
}
</code></pre>

<p>Note: There is index <code>0</code> coz the object that you are checking is an element 0 of the array <code>obj</code></p>

<hr>

<p>Here is a fiddle:</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>var obj = [{
		"7364234":"hsjd",
		"tom and jerry":"dsjdas",
		"mickey mouse":"kfjskdsad",
		"popeye the sailor man":"alkdsajd",
		"the carribean":"kasjdsjad"
	}];

	if ( typeof obj[0]["the carribean"] !== 'undefined' ) {
		console.log('exists');
	} else {
		console.log('does not exist');
	}</code></pre>
</div>
</div>
</p>

<hr>

<p>As suggested by Cristy below, you can also use <code>obj[0][val] === undefined</code></p>

<p>You can also:</p>

<pre><code>var obj = [{
    "7364234":"hsjd",
    "tom and jerry":"dsjdas",
    "mickey mouse":"kfjskdsad",
    "popeye the sailor man":"alkdsajd",
    "the carribean":"kasjdsjad"
}];

var val = "7364234";

if ( val in obj[0] ) {
    console.log('exists');
} else {
    console.log('does not exist');
}
</code></pre>


blocks|key|2412468|text|您的obj是一个数组，因此要检测数组中的任何对象中是否存在密钥，则需要迭代数组，然后查看每个对象的键。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2412469|​|2412470|var+objArr+=+[{
++"7364234":+"hsjd",
++"tom+and+jerry":+"dsjdas",
++"mickey+mouse":+"kfjskdsad",
++"popeye+the+sailor+man":+"alkdsajd",
++"the+carribean":+"kasjdsjad"
}]

const+contains+=+(string)+=>
++objArr.findIndex(
++++//+Is+the+string+contained+in+the+object+keys?
++++obj+=>+Object.keys(obj).includes(string)
++)+!==+-1

console.log(contains('the+carribean'))
console.log(contains('spaghetti'))|code-block|syntax|javascript|2412471|2412472|entityMap^0|2|3|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>Your <code>obj</code> is an array so to detect if the key exists in any of the objects in the <em>array</em> you need to iterate the array for then look at each object's keys.</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>var objArr = [{
  "7364234": "hsjd",
  "tom and jerry": "dsjdas",
  "mickey mouse": "kfjskdsad",
  "popeye the sailor man": "alkdsajd",
  "the carribean": "kasjdsjad"
}]

const contains = (string) =&gt;
  objArr.findIndex(
    // Is the string contained in the object keys?
    obj =&gt; Object.keys(obj).includes(string)
  ) !== -1

console.log(contains('the carribean'))
console.log(contains('spaghetti'))</code></pre>
</div>
</div>
</p>


blocks|key|20360|text|您可以筛选对象数组，并只返回具有所需键的对象。如果结果数组的长度大于零，则意味着存在具有该键的元素。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|20361|var+obj+=+[{
++++"7364234":"hsjd",
++++"tom+and+jerry":"dsjdas",
++++"mickey+mouse":"kfjskdsad",
++++"popeye+the+sailor+man":"alkdsajd",
++++"the+carribean":"kasjdsjad"
}];

var+val+=+"the+carribean";

var+exists+=+obj.filter(function+(o)+{
++return+o.hasOwnProperty(val);
}).length+>+0;

if+(exists)+{
++++console.log('exists');
}+else+{
++++console.log('does+not+exist');
}|code-block|syntax|javascript|20362|如果数组包含具有所需键的对象，则将返回true，而不管其值是undefined还是null。|offset|length|style|CODE|20363|entityMap^0|0|0|J|4|U|9|15|4|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|N|$]]

<p>You can filter the objects array and return only the objects which have the desired key. Then if the resulting array has a length greater than zero, it means that there are elements having that key.</p>

<pre><code>var obj = [{
    "7364234":"hsjd",
    "tom and jerry":"dsjdas",
    "mickey mouse":"kfjskdsad",
    "popeye the sailor man":"alkdsajd",
    "the carribean":"kasjdsjad"
}];

var val = "the carribean";

var exists = obj.filter(function (o) {
  return o.hasOwnProperty(val);
}).length &gt; 0;

if (exists) {
    console.log('exists');
} else {
    console.log('does not exist');
}
</code></pre>

<p>This will return <code>true</code> if the array contains objects which have the desired key no matter if its value is <code>undefined</code> or <code>null</code>.</p>


blocks|key|2412529|text|这是因为您有一个对象数组(+[{...},{...}]+)，而不仅仅是一个对象{...}。要么使用对象并保留测试，要么使用Array.find方法搜索数组中是否存在具有val属性的对象。例：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2412530|var+objArr+=+[{
++++"7364234":"hsjd",
++++"tom+and+jerry":"dsjdas",
++++"mickey+mouse":"kfjskdsad",
++++"popeye+the+sailor+man":"alkdsajd",
++++"the+carribean":"kasjdsjad"
}]

let+val+=+$("input[name='type_ahead_input']").val();

var+existingObj+=+objArr.find(function(element)+{
++return+typeof+element[val]+!==+'undefined';
});

if+(existingObj[val])+{
console.log('was+found');
}+else+{
console.log('not-found');|code-block|syntax|javascript|2412531|请参阅：globaux/Array/find|2412532|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Objets_globaux/Array/find^0|E|D|13|5|2C|3|0|0|4|I|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|12|8|@]|D|@$9|13|A|14|1|15]]|E|$]]|$1|M|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

<p>It's because you have an array of objects <code>[{...},{...}]</code> and not just an object <code>{...}</code>.
Either use an object and keep your test, or use the Array.find method to search if an object with the <code>val</code>property exists in you array. Ex :</p>

<pre><code>var objArr = [{
    "7364234":"hsjd",
    "tom and jerry":"dsjdas",
    "mickey mouse":"kfjskdsad",
    "popeye the sailor man":"alkdsajd",
    "the carribean":"kasjdsjad"
}]

let val = $("input[name='type_ahead_input']").val();

var existingObj = objArr.find(function(element) {
  return typeof element[val] !== 'undefined';
});

if (existingObj[val]) {
console.log('was found');
} else {
console.log('not-found');
</code></pre>

<p>See : <a href="https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Objets_globaux/Array/find" rel="nofollow noreferrer">https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Objets_globaux/Array/find</a></p>


blocks|key|997685|text|您需要从数组obj[0][val]获取对象。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|997686|​|997687|var+validate+=+function()+{
++var+obj+=+[{
++++"7364234":+"hsjd",
++++"tom+and+jerry":+"dsjdas",
++++"mickey+mouse":+"kfjskdsad",
++++"popeye+the+sailor+man":+"alkdsajd",
++++"the+carribean":+"kasjdsjad"
++}];

++var+val+=+$("input[name='type_ahead_input']").val();
++console.log(val);
++if+(obj[0][val])+{
++++console.log('exists');
++}+else+{
++++console.log('does+not+exist');
++}
}|code-block|syntax|javascript|997688|<script+src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<input+name="type_ahead_input"+value=""+onkeyup="validate()">|997689|997690|entityMap^0|6|B|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|V|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|J|7|W|8|@]|D|@]|E|$K|L]]|$1|O|3|G|5|6|7|X|8|@]|D|@]|E|$]]|$1|P|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|Q|$]]

<p>You need to get the object from the array <code>obj[0][val]</code></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>var validate = function() {
  var obj = [{
    "7364234": "hsjd",
    "tom and jerry": "dsjdas",
    "mickey mouse": "kfjskdsad",
    "popeye the sailor man": "alkdsajd",
    "the carribean": "kasjdsjad"
  }];

  var val = $("input[name='type_ahead_input']").val();
  console.log(val);
  if (obj[0][val]) {
    console.log('exists');
  } else {
    console.log('does not exist');
  }
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"&gt;&lt;/script&gt;

&lt;input name="type_ahead_input" value="" onkeyup="validate()"&gt;</code></pre>
</div>
</div>
</p>


blocks|key|997710|text|@E.Sundin回答是我认为最简单的。就我的案子来说，我做得很好.|type|unstyled|depth|inlineStyleRanges|entityRanges|data|997711|let+o+=+{+
++++id:+2,+
++++name:+"jack",+
++++age:+54,+temp:+2323
}

if(!Object.keys(o).includes('id'))+throw+new+BadRequest("Id+was+missing!");|code-block|syntax|javascript|997712|如果有一个通过循环完成的对象数组。|997713|if(!o.every(elm+=>+Object.keys(o).includes('id'))+throw+new+BadRequest("Id+was+missing!");|997714|希望它能成功。|997715|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

<p>@E. Sundin answer is the simplest I think. For my case, I was done like below ...</p>
<pre class="lang-js prettyprint-override"><code>let o = { 
    id: 2, 
    name: &quot;jack&quot;, 
    age: 54, temp: 2323
}

if(!Object.keys(o).includes('id')) throw new BadRequest(&quot;Id was missing!&quot;);
</code></pre>
<p>If you have an array of objects done by a loop through.</p>
<pre class="lang-js prettyprint-override"><code>if(!o.every(elm =&gt; Object.keys(o).includes('id')) throw new BadRequest(&quot;Id was missing!&quot;);
</code></pre>
<p>Hopefully, it'll work.</p>


blocks|key|20430|text|我建议使用Array.some()来知道键是否存在，使用Array.find()获取找到的键的值，同时使用一些最近的语法：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|20431|let+arr+=+[{"foo":+1},+{"bar":2}];

function+isKeyInArray(array,+key)+{+
++return+array.some(obj+=>+obj.hasOwnProperty(key));+
}

function+getValueFromKeyInArray(array,+key)+{+
++return+array.find(obj+=>+obj[key])?.[key];+
}

console.log(isKeyInArray(arr,+"foo"),+isKeyInArray(arr,+"bar"),+isKeyInArray(arr,+"baz"));
console.log(getValueFromKeyInArray(arr,+"foo"),+getValueFromKeyInArray(arr,+"bar"),+getValueFromKeyInArray(arr,+"baz"));|code-block|syntax|javascript|20432|entityMap^0|5|C|S|C|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

<p>I suggest using <code>Array.some()</code> to know if a key exists and  <code>Array.find()</code> to get the value of the found key, together with some recent syntax:</p>
<pre class="lang-js prettyprint-override"><code>let arr = [{&quot;foo&quot;: 1}, {&quot;bar&quot;:2}];

function isKeyInArray(array, key) { 
  return array.some(obj =&gt; obj.hasOwnProperty(key)); 
}

function getValueFromKeyInArray(array, key) { 
  return array.find(obj =&gt; obj[key])?.[key]; 
}

console.log(isKeyInArray(arr, &quot;foo&quot;), isKeyInArray(arr, &quot;bar&quot;), isKeyInArray(arr, &quot;baz&quot;));
console.log(getValueFromKeyInArray(arr, &quot;foo&quot;), getValueFromKeyInArray(arr, &quot;bar&quot;), getValueFromKeyInArray(arr, &quot;baz&quot;));
</code></pre>


<p>I am trying to find out if the given key exists in array of object. if the value key exists then i want to return true else false.</p>

<p>i giving input of key from text box and then checking if the key exists in array of objects, but i couldn't get it.</p>

<p>here is what i have tried</p>

<p>code:</p>

<pre><code>var obj = [{
    "7364234":"hsjd",
    "tom and jerry":"dsjdas",
    "mickey mouse":"kfjskdsad",
    "popeye the sailor man":"alkdsajd",
    "the carribean":"kasjdsjad"
}]

var val = $("input[name='type_ahead_input']").val();

if (obj[val]) {
    console.log('exists');
} else {
    console.log('does not exist');
}
</code></pre>

<p>if i give input as '<code>the carribean</code>' which exists in array of object, even then its outputting in console as does not exist.</p>

<p>how can i resolve this?</p>


How to check if key exists in array of object

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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我正在试图找出给定的键是否存在于对象数组中。如果值键存在，那么我想返回true else。我从文本框输入键，然后检查该键是否存在于对象数组中，但无法得到。这是我尝试过的代码：var obj = [{    "7364234":"hsjd",    "tom and jerry":"dsjdas",    "mickey...

问如何检查对象数组中是否存在键
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问如何检查对象数组中是否存在键EN