Query JavaScript Object group by

问题

I have a JavaScript object like this:

[{"a":1,"b":2},{"a":1,"b":3},{"a":2,"b":4},{"a":2,"b":5}]

I want to group this object field 'a' and want something like this:

[{"a":1,"values":[{"a":1,"b":2},{"a":1,"b":3}]},{"a":2,"values":[{"a":2,"b":4},{"a":2,"b":5}]}]

I have a JavaScript array of more than few thousands elements. What is the most efficient way to achieve this?

回答1:

Underscore JS provides nice methods for structuring your models and grouping/filtering them.

http://underscorejs.org/#groupBy

回答2:

Try this code:

var data = [{"a":1,"b":2},{"a":1,"b":3},{"a":2,"b":4},{"a":2,"b":5}];

var res = alasql('SELECT a, ARRAY(_) AS [values] FROM ? GROUP BY a',[data]);

Here ARRAY(_) is a special aggregation function which saves current record(_) into the array with name values.

You can play with this example in jsFiddle.

来源：https://stackoverflow.com/questions/35405937/query-javascript-object-group-by