Javascript sort by 2 attributes

javascript_sort_by_2_attrs.js

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

JSON.stringify(ary.sort());
"[{"a":1,"b":2,"c":3},{"a":3,"b":5,"c":3},{"a":2,"b":3,"c":3},{"a":2,"b":2,"c":3},{"a":3,"b":4,"c":3},{"a":3,"b":3,"c":3}]"

JSON.stringify(ary.sort(function(x,y){return x['a'] - y['a']}))
"[{"a":1,"b":2,"c":3},{"a":2,"b":3,"c":3},{"a":2,"b":2,"c":3},{"a":3,"b":5,"c":3},{"a":3,"b":4,"c":3},{"a":3,"b":3,"c":3}]"

JSON.stringify(ary.sort(function(x,y){return [x['a'] - y['a'],x['b']-y['b']]}))
"[{"a":1,"b":2,"c":3},{"a":2,"b":3,"c":3},{"a":2,"b":2,"c":3},{"a":3,"b":5,"c":3},{"a":3,"b":4,"c":3},{"a":3,"b":3,"c":3}]"

JSON.stringify(ary.sort(function(x,y){return x['a'] - y['a'] || x['b']-y['b']}))
"[{"a":1,"b":2,"c":3},{"a":2,"b":2,"c":3},{"a":2,"b":3,"c":3},{"a":3,"b":3,"c":3},{"a":3,"b":4,"c":3},{"a":3,"b":5,"c":3}]"