javascript - Underscore findWhere function to find element match condition a or b - Stack Overflow

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I have an array of objects

var arr = [{a:1},{a:5}, {a:6},{a:11}];

I want to use underscore find where function to retrieve object satisfying condition a = 1 or a =11

like:

_findWhere(arr, {a:1} || {a:11})

Anything like this is possible ??

I have an array of objects

var arr = [{a:1},{a:5}, {a:6},{a:11}];

I want to use underscore find where function to retrieve object satisfying condition a = 1 or a =11

like:

_findWhere(arr, {a:1} || {a:11})

Anything like this is possible ??

• javascript
• underscore.js

Share Improve this question Follow edited Mar 25, 2016 at 18:14 Shaffiulla Khan 10.4k1616 gold badges5757 silver badges5454 bronze badges asked Mar 23, 2016 at 17:22 anandharshananandharshan 6,37244 gold badges3737 silver badges3535 bronze badges

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4 Answers 4

Sorted by: Reset to default 8

find behaves like findWhere in that it returns the first item that passes the search criteria. With find you can use a predicate to specify the search criteria.

var result = _.find(arr, function(item) {
    return item.a == 1 || item.a == 11;
});

you can use _.filter for this

var arr = [{a:1}, {a:5}, {a:6}, {a:11}];
_.filter(arr,function(n){return (n.a===1 || n.a===11)});

But there is a better solution which can help you adding as many or as you want. Using _.mixin you can create your own or function

var arr = [{a:1}, {a:5}, {a:6}, {a:11}];
_.mixin({
   or: function(obj,arr,condition){
     return _.chain(arr).where(condition).union(obj).value();
   }
});

_.chain(arr).where({a:1}).or(arr,{a:11}).or(arr,{a:2}).value();//returns 2 objects
_.chain(arr).where({a:1}).or(arr,{a:11}).or(arr,{a:5}).value();//returns 3 objects
_.chain(arr).where({a:1}).or(arr,{a:11}).value();//returns 2 objects

var arr2 = [{a:1,b:4}, {a:5}, {a:6}, {a:11}];
_.chain(arr2).where({a:1}).or(arr2,{a:11}).value();//returns 2 objects

For your case better to use find function. You can use function that passed as a second argument to find method and checks your two conditions:

var arr = [{ a: 1 }, { a: 5 }, { a: 6 }, { a: 11 }];

var elem = _.find(arr, function(e) {
    return e.a == 1 || e.a == 11;
});

document.write(JSON.stringify(elem));

<script src="https://cdnjs.cloudflare./ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>

---

Or using plain javascript (ES2015):

var arr = [{ a: 1 }, { a: 5 }, { a: 6 }, { a: 11 }];

var elem = arr.find(function(e) {
    return e.a == 1 || e.a == 11;
});

document.write(JSON.stringify(elem));

You could write it in plain Javascript with Array#some

var arr = [{ a: 1 }, { a: 5 }, { a: 6 }, { a: 11 }, { a: 11 }],
    found = function (array) {
        var index;
        return arr.some(function (a, i) {
            if (a.a === 1 || a.a === 11) {
                index = i;
                return true;
            }
        }) && array[index] || undefined;
    }(arr);

document.write('<pre>' + JSON.stringify(found, 0, 4) + '</pre>');

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