[英]Using Underscore.js to filter an array of objects on a property using a 'contains'
I have an array of objects which I would like to filter using a contains/any method on a property using underscore. 我有一个对象数组,我想使用下划线在属性上使用contains / any方法进行过滤。
For example, if I had the following variables: 例如,如果我有以下变量:
var people = [
{
name: 'Dave',
age: 26
},
{
name: 'Frank',
age: 23
}];
var allowedAges = [20, 23, 24];
I would like to use underscore to end up with a result like: 我想用下划线结果如下:
var allowedPeople = [];
_.each(_.where(people, { age: _.any()}), function (person) {
allowedPeople.push(person);
});
And there may also be occasions where allowedAges is an array of objects and id want to use the contains/any on the people array using a property of the objects in allowedAges. 并且有些情况下allowedAges是一个对象数组,而id想要使用allowedAges中对象的属性在people数组上使用contains / any。
The JS equivalent of contains
is usually indexOf
(and find
in rare cases). JS的等价物contains
通常是indexOf
(在极少数情况下find
)。
You can use the built-in Array.prototype.filter
to do this like: 您可以使用内置的Array.prototype.filter
来执行以下操作:
people.filter(function (person) {
return allowedAges.indexOf(person.age) !== -1; // -1 means not present
});
or with underscore, using the same predicate: 或者使用下划线,使用相同的谓词:
_.filter(people, function (person) {
return allowedAges.indexOf(person.age) !== -1; // -1 means not present
}
If you have access to ES6 collections or a polyfill for Set
, you can replace the allowedAges
array with a set (enforcing unique values) and simply use Set.prototype.has
: 如果您可以访问ES6集合或Set
的allowedAges
,则可以使用set(强制唯一值)替换allowedAges
数组,并只使用Set.prototype.has
:
people.filter(person => allowedAges.has(person.age))
For the sake of completeness, here's an underscore solution that works with a mixed array of integers and objects containing an age
property. 为了完整起见,这里是一个下划线解决方案,它使用包含age
属性的整数和对象的混合数组。
var allowedPeople = _.filter(people, (p) =>
_.some(allowedAges, (a) => (a.age || a) === p.age)
);
This is a pure JS version: 这是一个纯JS版本:
var people = [{ name: 'Dave', age: 26 }, { name: 'Frank', age: 23 }]; var allowedAges = [20, 23, 24]; function filterData(arr, key, searchList){ var result = []; if(Array.isArray(searchList)){ result = arr.filter(function(item){ return (searchList.indexOf(item[key])>-1); }); } else{ result = arr.filter(function(item){ return (searchList === item[key]); }); } return result; } document.write("<pre>" + JSON.stringify(filterData(people,"age", allowedAges), 0, 4) + "</pre>")
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