sort.js

var filter = [
  "all",
  [ "in", "$type", "Polygon", "LineString", "Point"],
  [ "all",
    ["in", "type", "town", "city"],
    ["==", "class", "street_limited"],
    [ "<=", "scalerank", 2]
  ]
]

var filter2 = [
  "all",
  [ "in", "$type", "Polygon", "Point", "LineString"],
  [ "all",
    ["in", "type", "city", "town"],
    ["==", "class", "street_limited"],
    [ "<=", "scalerank", 2]
  ]
]

var filter3 = [
  "all",
  [ "all",
    ["in", "type", "city", "town"],
    ["==", "class", "street_limited"],
    [ "<=", "scalerank", 2]
  ],
  [ "in", "$type", "Polygon", "Point", "LineString"]
]

var filter4 = [
  "all",
  [ "all",
    ["==", "class", "street_limited"],
    ["in", "type", "city", "town"],
    [ "<=", "scalerank", 2]
  ],
  [ "in", "$type", "Polygon", "Point", "LineString"]
]

var filter5 = [
  "all",
  [ "all",
    ["==", "class", "street_limited"],
    ["in", "type", "city", "town"],
    [ "<=", "scalerank", 2]
  ],
  [ "in", "$type", "Polygon", "Point", "LineString"]
]

function sortLevel(list) {
  if (!Array.isArray(list)) {
    return list;
  } else if (list[0] == 'any' || list[0] == 'all' || list[0] == 'none') {
    return list.slice(0, 1).concat(list.slice(1).map(sortLevel).sort());
  } else {
    return list.slice(0, 2).concat(list.slice(2).map(sortLevel).sort());
  }
}

console.log(sortLevel(filter));
console.log(sortLevel(filter2));
console.log(sortLevel(filter3));
console.log(sortLevel(filter4));

Is there a reliable source of metadata for which filter expressions are comparing against a property vs a set? It would be nice to not hard code 'any', 'all' and 'none'. (I don't think this metadata exists currently, we should create it)

Properties values inside set operations are required to be operations themselves (arrays). While non-set operations are individual values (non-arrays). The .map(sortLevel) on line 57 is unnessesary.

It would be nice to have this method inside the style spec so it can grow and evolve with the spec.

The filter operator list is just a list, doesn't divide into set vs property https://github.com/mapbox/mapbox-gl-style-spec/blob/mb-pages/reference/v8.json#L790