I have an array of objects, each object contains n key/value pairs. I need to return an array of the objects which has a value matching x.
Using Underscore.js I could use _.findWhere however I don't know what key the value will be under.
I could obviously loop the array, fetch all of the keys in each object, then run _.findWhere on each key and check if the value is there, but it doesn't seem like a good way of doing this.
I could obviously loop the array, fetch all of the keys in each object...
Yes.
Write a function that accepts an array and a value to look for in its elements members, loop over the array, loop over the keys of the current element, and push the objects containing a member with a matching value to an array and return it after the iteration.
function findValues (arr,val) {
var result = [];
for (var i=0,current;i<arr.length;i++) {
current = arr [i];
for (var key in current) {
if (current [key] === val) {
result.push (current);
}
}
}
return result
}
Here is an example output
findValues (
[{
a:1,
b:2,
c:3
},{
a:1,
b:2,
},{
a:1,
b:2,
},{
a:1,
b:2,
c:3,
d:4
},{
a:1,
b:2,
}],
3
) //[{"a":1,"b":2,"c":3},{"a":1,"b":2,"c":3,"d":4}]
I think, that the best way is:
Object.prototype.someProperty = function(fn){
for (var key in this) {
if (fn(key, this[key])) return true;
}
return false;
};
Array.prototype.filter = function(fn) {
var a = [],
l = this.length;
for (var i = 0; i < l; i++) {
if (fn(this[i])) a.push(this[i]);
}
return a;
};
// test
var a = [
{a: 6, b: 8}
,{f: 7, c: 6, d: 67}
,{d: 4, c: 5, g: 8}
];
var b = a.filter(function(item){
return item.someProperty(function(k, v){
return v == 8;
});
});
console.dir(b);
This should do the trick:
var filteredList = _.filter(values, function(value){
return _.contains(value, 3);
});
