I need to send multiple array as parameters, not only 2 (yes I'm using _underscore in order to check for duplicate entries)
function arrayMerge(arr1, arr2) {
arr1 = Object.prototype.toString.call(arr1) === '[object Array]' ? arr1 : [];
arr2 = Object.prototype.toString.call(arr2) === '[object Array]' ? arr2 : [];
return _.uniq(arr1.concat(arr2));
}
How can I achieve this ? I would like to send not 2, but multiples arrays as parameters.
The version that also checks for array type like in your original code:
function arrayMerge() {
return _.chain(arguments).filter(_.isArray).flatten().unique().value();
}
The demo is below.
function arrayMerge() {
return _.chain(arguments).filter(_.isArray).flatten().unique().value();
}
var result = arrayMerge([1,2,3],[1,3,4],'test',[2,3,4,5]);
document.write(JSON.stringify(result));<script src="//cdnjs.cloudflare.com/ajax/libs/underscore.js/1.7.0/underscore-min.js"></script>You can use arguments. The variable arguments is an array of all the arguments passed to a function. So you can try this:
function merge() {
return _.uniq(Array.prototype.concat.apply([], arguments));
}
I have no experience with underscore but this should work.
Due to the behavior of concat, calling merge([3, 4, 5], null, 6) will result in [3, 4, 5, null, 6].
To ensure that all are arrays:
for (var i = 0; i < arguments.length; ++i) {
if (Object.prototype.toString.call(arguments[i]) !== '[object Array]') {
throw new Error(arguments[i] + " is not an array"); // Or do whatever you want
}
}
Soktinpk's answer is best for ES5.
If you are able to use ES6, you can make it a bit more explicit using rest parameters
function merge(...arrays) {
return _.uniq(Array.prototype.concat.apply([], arrays));
}
argumentsarray:arguments[0] === arr1in your case. Iterate overargumentsto get each array._.union()for that_.union([1,4,6,9], [1,4,12,5], [5,0,10,100], [1]).join("") === _.uniq([1,4,6,9].concat([1,4,12,5]).concat([5,0,10,100]).concat([1])).join("")