I have this array:
[{name: 'Brad', age: 30, isOlder: true, youngerBrother: 'Oleg'}, {name: 'Brad', age: 30, isOlder: false, youngerBrother: 'Michael'}]
I want to check if the items on the list are duplicated by specific keys.
for example - if name, age are the same on the list, the rows are duplicated, without paying attention to isOlder or youngerBrother.
I tried to use lodash _uniq but there is no option for excluding keys/paying attention to specific keys
You can use .filter() and .some():
var list = [
{name: 'Brad', age: 30, isOlder: true, youngerBrother: 'Oleg'},
{name: 'Brad', age: 30, isOlder: false, youngerBrother: 'Michael'}
];
list = list.filter(function(outer, oPos) {
return !list.some(function(inner, iPos) {
return iPos > oPos && inner.name == outer.name && inner.age == outer.age;
});
});
console.log(list);However, it would be more efficient to start the inner loop at oPos + 1 directly:
var list = [
{name: 'Brad', age: 30, isOlder: true, youngerBrother: 'Oleg'},
{name: 'Brad', age: 30, isOlder: false, youngerBrother: 'Michael'}
];
list = list.filter(function(outer, oPos) {
for(var iPos = oPos + 1; iPos < list.length; iPos++) {
if(list[iPos].name == outer.name && list[iPos].age == outer.age) {
return false;
}
}
return true;
});
console.log(list);Alternatively, we can build a list of the encountered composite keys as we are iterating in .filter(). Most browsers should implement if(keyList[key]) as a lookup in a hash table, making it quite fast.
var list = [
{name: 'Brad', age: 30, isOlder: true, youngerBrother: 'Oleg'},
{name: 'Brad', age: 30, isOlder: false, youngerBrother: 'Michael'}
];
var keyList = {};
list = list.filter(function(obj) {
var key = obj.name + '|' + obj.age;
if(keyList[key]) {
return false;
}
keyList[key] = true;
return true;
});
console.log(list);You could use lodash _.uniqBy(arr,'key') it would suit you, as you are already using lodash
Here's one option of doing this:
arr = [
{name: 'Brad', age: 30, isOlder: true, youngerBrother: 'Oleg'},
{name: 'Brad', age: 30, isOlder: false, youngerBrother: 'Michael'}
];
var result = checkDuplicateKeys(arr[0], arr[1], ['name', 'age']);
console.log(result);
function checkDuplicateKeys(obj1, obj2, keyList) {
var propertyDuplicateCounter = 0;
var result = false;
for (var i=0; i<keyList.length; i++) {
if (obj1.hasOwnProperty(keyList[i]) && obj2.hasOwnProperty(keyList[i])) {
propertyDuplicateCounter += 1;
}
}
if (propertyDuplicateCounter == keyList.length) {
result = true;
}
return result;
}
You could use Array#some and if name - age for any two or more objects are the same it will return true else false
var ar = [{name: 'Brad', age: 30, isOlder: true, youngerBrother: 'Oleg'}, {name: 'Brad', age: 30, isOlder: false, youngerBrother: 'Michael'}];
var result = ar.some(function(e) {
if(!this[e.name + '|' + e.age]) {
this[e.name + '|' + e.age] = true;
} else {
return true;
}
}, {});
console.log(result)Please try this
function isDuplicate(ArrayVar) {
var tempObj = {};
for (var key in ArrayVar) {
if (object.hasProperty(ArrayVar[key].name)) {
return true;
}
obj[ArrayVar[key].name] = true;
}
return false;
}
Try uniqBy + a callback to extract a compound key from an array item:
uniqs = _.uniqBy(yourArray, x => x['name'] + x['age'])
In pure JS:
uniqBy = (xs, key) => {
var keys = xs.map(key);
return xs.filter((x, i) => keys.indexOf(key(x)) === i);
};
uniqs = uniqBy(yourArray, x => x['name'] + x['age'])
See https://stackoverflow.com/a/9229821/989121 for more details.
You can use Array.prototype.filter
var data = [
{name: 'Brad', age: 30, isOlder: true, youngerBrother: 'Oleg'},
{name: 'Brad', age: 30, isOlder: false, youngerBrother: 'Michael'}
];
function distinctByField(arr, field) {
var result = arr.filter(function(item) {
var key = item[field];
return this[key] ? false : (this[key] = true);
}, Object.create(null));
return result;
}
console.log(distinctByField(data, 'age'));