Given an array of objects, find the object with a particular key

问题

Given an array of objects, what is the best way to find the object with a particular key in JS?

Using jQuery and underscoreJS is fine. I'm just looking for the easiest / least code answer.

Example: An array of objects, where each object has a "name". Find the object with a particular "name".

var people = [{name: "A"}, {name: "B"}, {name: "C"}];

My current solution: Pass in the array, the key (e.g. "name"), and the value (e.g. "C").

function getObject(myArray, searchKey, searchValue) {
  myArray.forEach(function(element){
    if (element[searchKey] == searchValue) {
      return element;
    }
  });
}

回答1:

You can use Underscore.js's _.where function, like this

console.log(_.where(people, {
    "name": "C"
}));
# [ { name: 'C' } ]

This returns all the objects in the array, which exactly matches the object we pass as the second argument.

回答2:

You should go with grep of jQuery

var people = [{name: "A"}, {name: "B"}, {name: "C"}];

var obj1= jQuery.grep(people,function(n,i){return (n.name=='A')})

回答3:

Using _.filter:

var people = [{name: "A"}, {name: "B"}, {name: "C"}];

var filteredPeople = _.filter(people, function(obj){
    return obj['name'] == 'C';
});

console.log(JSON.stringify(filteredPeople)) // [{"name":"C"}]

If you want an array without the matched object(s), use _.reject:

var filteredPeople = _.reject(people, function(obj){
    return obj['name'] == 'C';
});

console.log(JSON.stringify(filteredPeople)) // [{name: "A"}, {name: "B"}]

回答4:

Without any custom library you can also do this. Please take a look at the following code

var people = [{name: "A"}, {name: "B"}, {name: "C"}],
    match=function(element){
      return element.name==="A";
    };
console.log(people.filter(match));

But it is kind of static code . I don't know how to pass the key and value to the match() function.

回答5:

I'm surprised not to find the obvious answer here, so: To do that with Underscore, you'd use _.find:

function getObject(myArray, searchKey, searchValue) {
    return _.find(myArray, function(entry) { return entry[seachKey] === searchValue; });
}

You don't need Underscore for this, though; JavaScript's array type has find (as of ES5):

function getObject(myArray, searchKey, searchValue) {
    return myArray.find(function(entry) { return entry[searchKey] === searchValue; });
}

As of ES2015+, you can make it more concise with an arrow function and destructuring:

function getObject(myArray, searchKey, searchValue) {
    return myArray.find(({[searchKey]: value}) => value === searchValue);
}

Live example of that last one:

function getObject(myArray, searchKey, searchValue) {
    return myArray.find(({[searchKey]: value}) => value === searchValue);
}

const people = [{name: "A"}, {name: "B"}, {name: "C"}];
console.log(getObject(people, "name", "C"));

来源：https://stackoverflow.com/questions/26728022/given-an-array-of-objects-find-the-object-with-a-particular-key

标签

javascript

jquery

arrays

underscore.js