javascript 使用 lodash 查找匹配值（如果存在）
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Use lodash to find a matching value if it exists
提问by PhoonOne
I have the following:
我有以下几点：
myArray = [{
"urlTag": "Google",
"urlTitle": "Users",
"status": 6,
"nested": {
"id": 2,
"title": "http:\/\/www.google.com",
}
},
{
"urlTag": "Bing",
"tabTitle": "BingUsers"
}]
I have myUrlTagToSearch = "Yahoo", I want to loop through myArray, check if any urlTagis equal to "Yahoo", if yes: return "Yahoo", if not: just return a empty string (""). In this example, it should return ""because there are only "Google"and "Bing".
我有myUrlTagToSearch = "Yahoo"，我想循环myArray，检查是否有任何urlTag等于"Yahoo"，如果是：返回"Yahoo"，如果不是：只返回一个空字符串（""）。在这个例子中，它应该返回，""因为只有"Google"and "Bing"。
Can I do this with lodash?
我可以用 lodash 做到这一点吗？
回答by James Donnelly
You can use lodash's find()methodmixed with a regular conditional (if) statement to do this.
您可以将lodash 的find()方法与常规条件 ( if) 语句混合使用来执行此操作。
For starters, to search the array, you can use:
对于初学者，要搜索数组，您可以使用：
var result = _.find(myArray, { "urlTag": "Yahoo" });
You can replace "Yahoo"with your myUrlTagToSearchvariable here.
您可以在此处替换"Yahoo"为您的myUrlTagToSearch变量。
If no matches are found it'll return undefined, otherwise it'll return the matching Object. As Objects are truthyvalues and undefinedis a fasleyvalue, we can simply use resultas the condition within an ifstatement:
如果未找到匹配项，它将返回undefined，否则将返回匹配的Object。由于对象是真值并且undefined是fasley值，我们可以简单地result在if语句中用作条件：
if (result)
return "Yahoo";
else
return "";
We don't even need to define resulthere, as we can simply use:
我们甚至不需要在result这里定义，因为我们可以简单地使用：
if ( _.find(myArray, { "urlTag": "Yahoo" }) )
return "Yahoo";
else
return "";
Or even:
甚至：
return _.find(myArray, { "urlTag": "Yahoo" }) ? "Yahoo" : "";
回答by Andy
You probably cando this with lodash (I don't know much about lodash), but in case no-one else answers there is a simple vanilla JS solution:
你可能可以用 lodash来做到这一点（我对 lodash 不太了解），但如果没有其他人回答，有一个简单的 vanilla JS 解决方案：
function exists(site) {
return myArray.some(function (el) {
return el.urlTag === site;
}) === false ? '': site;
}
exists('Yahoo');
