var _ = require('lodash');
var users = [
{ 'id': '1', 'coins': false },
{ 'id': '2', 'coins': false }
];
var a = _.every(users, function(p){
if ('id' in p && 'coins' in p)
return true;
else
return false;
});
console.log(a);
The function works to check in keys exists in an array of objects. If one of the object doesn't exists "id" or "coins" , it return false.
Is there a better way to write thie snippet of code? I felt quite clumsy.
Since you're in node.js, you know you already have array.every() so I don't see any reason for lodash here or for the if/else. Why not this:
var users = [
{ 'id': '1', 'coins': false },
{ 'id': '2', 'coins': false }
];
var allValid = users.every(function(item) {
return 'id' in item && 'coins' in item;
});
FYI, this code is assuming nobody has mysteriously added properties named id or coins to the Object.prototype (which seems like a safe assumption here). If you wanted to protect against that, you could use item.hasOwnProperty('id') instead of in.
At very least, replace:
if ('id' in p && 'coins' in p)
return true;
else
return false;
With:
return 'id' in p && 'coins' in p;
Basically, never use a construct like:
if (x)
return true;
else
return false;
x is already a boolean, or at least a truthy / falsy value.
In case you need to be sure the returned value is a boolean, just force it to one:
return !!('id' in p && 'coins' in p);
Also, as mentioned in the other answer, lodash is redundant, here. You canuse JS's native [every][3].
Replace:
_.every(users, function(p){
With:
users.every(function(p){
x is not necessarily a boolean... It is in this particular case, but not always.
!! here. The in operator already returns a boolean.
if (x) test that wasn't correct.You can use _.has() to check if an object property exists:
function checkValidity(array, listOfKeys) {
return _.every(array, function (item) {
return _.every(listOfKeys, function (key) {
return _.has(item, key);
});
});
}
Usage:
checkValidity(users, ['id', 'coins']);
I'd use the [Array.prototype.some()][1] function:
var users = [
{ 'id': '1', 'coins': false },
{ 'id': '2', 'coins': false }
];
var result = users.some(e => e.hasOwnProperty('id') && e.hasOwnProperty('coins'));
console.log("The array contains an object with a 'name' and 'quantity' property: " + result);
