I have some data
var data = [
{type: "A", role:[1,2]},
{type: "B", role:[2]},
{type: "C", role:[2,3]},
{type: "D", role:[3]}
];
I'm trying to sortBy 'role' using underscore.js
var groups = _(data).groupBy(function(el){
return el.role
}
);
Is there a easy way to get reapeated data like this
1: {
{type:"A" ...}
},
2: {
{type:"A" ...},
{type:"B" ...},
... etc
not like this http://jsbin.com/IzEwUkim/2/edit
You can, as usual, do it by hand with _.reduce, something like this:
var groups = _(data).reduce(function(memo, o) {
_(o.role).each(function(i) {
memo[i] = memo[i] || [ ];
memo[i].push(o);
});
return memo;
}, { });
Demo: http://jsfiddle.net/ambiguous/HDE3c/
You could use a plain for loop instead of _.each to iterate over the roles of course.
_.groupBy isn't going to work here as the function/key is always a single value so I think you're stuck unwrapping the role arrays by hand.
I know you asked for underscore, but here's native js:
var map = {};
data.forEach(function(obj){
obj.role.forEach(function(roleVal){
(map[roleVal] = map[roleVal] || []).push(obj);
});
});
console.log(map);
reduce if you wanted to skip the separate var map = { }. Nothing wrong with native solutions.