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(function() {
"use strict";
let t = db.slice1;
t.drop();
assert.commandWorked(t.insert({_id: 1, a: [0, 1, 2, 3, 4, 5, -5, -4, -3, -2, -1], b: 1, c: 1}));
// first three
let out = t.findOne({}, {a: {$slice: 3}});
assert.eq(out.a, [0, 1, 2], '1');
// last three
out = t.findOne({}, {a: {$slice: -3}});
assert.eq(out.a, [-3, -2, -1], '2');
// skip 2, limit 3
out = t.findOne({}, {a: {$slice: [2, 3]}});
assert.eq(out.a, [2, 3, 4], '3');
// skip to fifth from last, limit 4
out = t.findOne({}, {a: {$slice: [-5, 4]}});
assert.eq(out.a, [-5, -4, -3, -2], '4');
// skip to fifth from last, limit 10
out = t.findOne({}, {a: {$slice: [-5, 10]}});
assert.eq(out.a, [-5, -4, -3, -2, -1], '5');
// interaction with other fields
out = t.findOne({}, {a: {$slice: 3}});
assert.eq(out.a, [0, 1, 2], 'A 1');
assert.eq(out.b, 1, 'A 2');
assert.eq(out.c, 1, 'A 3');
out = t.findOne({}, {a: {$slice: 3}, b: true});
assert.eq(out.a, [0, 1, 2], 'B 1');
assert.eq(out.b, 1, 'B 2');
assert.eq(out.c, undefined);
out = t.findOne({}, {a: {$slice: 3}, b: false});
assert.eq(out.a, [0, 1, 2]);
assert.eq(out.b, undefined);
assert.eq(out.c, 1);
assert(t.drop());
assert.commandWorked(t.insert({
comments: [{id: 0, text: 'a'}, {id: 1, text: 'b'}, {id: 2, text: 'c'}, {id: 3, text: 'd'}],
title: 'foo'
}));
// $slice in an inclusion projection.
out = t.findOne({}, {comments: {$slice: 2}, irrelevantField: 1});
assert.eq(out.comments, [{id: 0, text: 'a'}, {id: 1, text: 'b'}]);
assert.eq(out.title, undefined);
// Check that on its own, $slice defaults to an exclusion projection.
out = t.findOne({}, {comments: {$slice: 2}});
assert.eq(out.comments, [{id: 0, text: 'a'}, {id: 1, text: 'b'}]);
assert.eq(out.title, 'foo');
// $slice in an exclusion projection (with explicit exclusions).
out = t.findOne({}, {comments: {$slice: 2}, title: 0});
assert.eq(out.comments, [{id: 0, text: 'a'}, {id: 1, text: 'b'}]);
assert.eq(out.title, undefined);
// nested arrays
assert(t.drop());
assert.commandWorked(t.insert({_id: 1, a: [[1, 1, 1], [2, 2, 2], [3, 3, 3]], b: 1, c: 1}));
out = t.findOne({}, {a: {$slice: 1}});
assert.eq(out.a, [[1, 1, 1]], 'n 1');
out = t.findOne({}, {a: {$slice: -1}});
assert.eq(out.a, [[3, 3, 3]], 'n 2');
out = t.findOne({}, {a: {$slice: [0, 2]}});
assert.eq(out.a, [[1, 1, 1], [2, 2, 2]], 'n 2');
// Test that $slice operator goes only 1 level deep into nested arrays.
assert(t.drop());
assert.commandWorked(t.insert([
{_id: 1, a: {b: [1, 2, 3]}},
{_id: 2, a: [{b: [1, 2, 3]}]},
{_id: 3, a: [[{b: [1, 2, 3]}]]},
{_id: 4, a: [[{b: [1, 2, 3]}], {b: [1, 2, 3]}, 1, null, {}]},
]));
out = t.find({}, {a: {b: {$slice: [1, 1]}}}).sort({_id: 1}).toArray();
assert.eq(out, [
{_id: 1, a: {b: [2]}},
{_id: 2, a: [{b: [2]}]},
{_id: 3, a: [[{b: [1, 2, 3]}]]},
{_id: 4, a: [[{b: [1, 2, 3]}], {b: [2]}, 1, null, {}]},
]);
function testSingleDocument(projection, input, expectedOutput, deleteId = true) {
assert(t.drop());
assert.commandWorked(t.insert(input));
const actualOutput = t.findOne({}, projection);
if (deleteId) {
delete actualOutput._id;
}
assert.eq(actualOutput, expectedOutput);
}
// Test nesting objects and arrays.
testSingleDocument({'a.b.c.d.e': {$slice: [1, 1]}},
{a: [{b: [{c: [{d: [{e: [1, 2, 3]}]}]}]}]},
{a: [{b: [{c: [{d: [{e: [2]}]}]}]}]});
// Test that inclusion, exclusion and expression projections have unlimited array depth in queries
// with $slice.
testSingleDocument({a: {b: {c: {$slice: [1, 1]}, d: 1}}},
{
a: [
{b: {c: [1, 2, 3], d: 123}},
[{b: {c: [1, 2, 3], d: 123}}, {b: {c: [4, 5, 6], d: 456}}],
{b: [{c: [1, 2, 3], d: 123}, {c: [4, 5, 6], d: 456}]},
{b: [[{c: [1, 2, 3], d: 123}], [{c: [4, 5, 6], d: 456}]]}
]
},
{
a: [
{b: {c: [2], d: 123}},
[{b: {c: [1, 2, 3], d: 123}}, {b: {c: [4, 5, 6], d: 456}}],
{b: [{c: [2], d: 123}, {c: [5], d: 456}]},
{b: [[{c: [1, 2, 3], d: 123}], [{c: [4, 5, 6], d: 456}]]}
]
});
testSingleDocument({a: {b: {c: {$slice: [1, 1]}, d: 0}}},
{
a: [
{b: {c: [1, 2, 3], d: 123}},
[{b: {c: [1, 2, 3], d: 123}}, {b: {c: [4, 5, 6], d: 456}}],
{b: [{c: [1, 2, 3], d: 123}, {c: [4, 5, 6], d: 456}]},
{b: [[{c: [1, 2, 3], d: 123}], [{c: [4, 5, 6], d: 456}]]}
]
},
{
a: [
{b: {c: [2]}},
[{b: {c: [1, 2, 3]}}, {b: {c: [4, 5, 6]}}],
{b: [{c: [2]}, {c: [5]}]},
{b: [[{c: [1, 2, 3]}], [{c: [4, 5, 6]}]]}
]
});
testSingleDocument({a: {b: {c: {$slice: [1, 1]}, d: {$add: [1, 2, 3]}}}},
{
a: [
{b: {c: [1, 2, 3], d: 123}},
[{b: {c: [1, 2, 3], d: 123}}, {b: {c: [4, 5, 6], d: 456}}],
{b: [{c: [1, 2, 3], d: 123}, {c: [4, 5, 6], d: 456}]},
{b: [[{c: [1, 2, 3], d: 123}], [{c: [4, 5, 6], d: 456}]]}
]
},
{
a: [
{b: {c: [2], d: 6}},
[{b: {c: [1, 2, 3], d: 6}}, {b: {c: [4, 5, 6], d: 6}}],
{b: [{c: [2], d: 6}, {c: [5], d: 6}]},
{b: [[{c: [1, 2, 3], d: 6}], [{c: [4, 5, 6], d: 6}]]}
]
});
testSingleDocument({a: {b: {c: {$slice: [1, 1]}, d: {$add: [{$abs: "$e"}, -4]}}}},
{
a: [
{b: {c: [1, 2, 3], d: 123}},
[{b: {c: [1, 2, 3], d: 123}}, {b: {c: [4, 5, 6], d: 456}}],
{b: [{c: [1, 2, 3], d: 123}, {c: [4, 5, 6], d: 456}]},
{b: [[{c: [1, 2, 3], d: 123}], [{c: [4, 5, 6], d: 456}]]}
],
e: -10
},
{
a: [
{b: {c: [2], d: 6}},
[{b: {c: [1, 2, 3], d: 6}}, {b: {c: [4, 5, 6], d: 6}}],
{b: [{c: [2], d: 6}, {c: [5], d: 6}]},
{b: [[{c: [1, 2, 3], d: 6}], [{c: [4, 5, 6], d: 6}]]}
]
});
// Test multiple $slice operators in the same projection.
testSingleDocument({a: {b: {c: {$slice: [1, 1]}, d: {$slice: -1}}}},
{
a: [
{b: {c: [1, 2, 3], d: [4, 5, 6]}},
[
{b: {c: [1, 2, 3], d: [4, 5, 6]}},
{b: {c: [7, 8, 9], d: [10, 11, 12]}}
],
{b: [{c: [1, 2, 3], d: [4, 5, 6]}, {c: [7, 8, 9], d: [10, 11, 12]}]},
{b: [[{c: [1, 2, 3], d: [4, 5, 6]}], [{c: [7, 8, 9], d: [10, 11, 12]}]]}
]
},
{
a: [
{b: {c: [2], d: [6]}},
[
{b: {c: [1, 2, 3], d: [4, 5, 6]}},
{b: {c: [7, 8, 9], d: [10, 11, 12]}}
],
{b: [{c: [2], d: [6]}, {c: [8], d: [12]}]},
{b: [[{c: [1, 2, 3], d: [4, 5, 6]}], [{c: [7, 8, 9], d: [10, 11, 12]}]]}
]
});
testSingleDocument({a: {b: {$slice: [1, 1]}}, c: {d: {$slice: -1}}},
{
a: [
{b: [1, 2, 3]},
[{b: [1, 2, 3]}, {b: [4, 5, 6]}],
{b: [[1, 2, 3], [4, 5, 6]]},
],
c: [
{d: [1, 2, 3]},
[{d: [1, 2, 3]}, {d: [4, 5, 6]}],
{d: [[1, 2, 3], [4, 5, 6], [7, 8, 9]]},
]
},
{
a: [
{b: [2]},
[{b: [1, 2, 3]}, {b: [4, 5, 6]}],
{b: [[4, 5, 6]]},
],
c: [
{d: [3]},
[{d: [1, 2, 3]}, {d: [4, 5, 6]}],
{d: [[7, 8, 9]]},
]
});
// Test that if $slice cannot be applied, the field value is still included in the output.
// Case when path for $slice contains object.
testSingleDocument({a: {$slice: 1}}, {a: {c: 123}}, {a: {c: 123}});
testSingleDocument({a: {$slice: 1}, d: 1}, {a: {c: 123}, d: 456}, {a: {c: 123}, d: 456});
testSingleDocument({a: {$slice: 1}, d: 0}, {a: {c: 123}, d: 456}, {a: {c: 123}});
// Case when path for $slice does not exist in the document.
testSingleDocument({a: {$slice: 1}}, {b: {e: 123}}, {b: {e: 123}});
testSingleDocument({a: {$slice: 1}, d: 1}, {b: {e: 123}, d: 456}, {d: 456});
testSingleDocument({a: {$slice: 1}, d: 0}, {b: {e: 123}, d: 456}, {b: {e: 123}});
// Case when path for $slice traverses through deep arrays.
testSingleDocument({'a.b.c': {$slice: 1}},
{a: [[[{b: [[[{c: [1, 2, 3]}]]]}]]]},
{a: [[[{b: [[[{c: [1, 2, 3]}]]]}]]]});
testSingleDocument({'a.b.c': {$slice: 1}, d: 1},
{a: [[[{b: [[[{c: [1, 2, 3]}]]]}]]], d: 456},
{a: [[[{b: [[[{c: [1, 2, 3]}]]]}]]], d: 456});
testSingleDocument({'a.b.c': {$slice: 1}, d: 0},
{a: [[[{b: [[[{c: [1, 2, 3]}]]]}]]], d: 456},
{a: [[[{b: [[[{c: [1, 2, 3]}]]]}]]]});
// Test that even though $slice cannot be applied to deep arrays, fields are still filtered in the
// objects inside these deep arrays for inclusion projections.
testSingleDocument({e: 1, 'a.b': {$slice: 1}},
{e: 123, a: [[[{b: [1, 2, 3], d: 4, f: 5}]]]},
{e: 123, a: [[[{b: [1, 2, 3]}]]]});
// Test $slice with an inclusion/exclusion projection for _id field.
testSingleDocument({_id: 1, a: {$slice: [1, 1]}},
{_id: 123, a: [1, 2, 3]},
{_id: 123, a: [2]},
false /* deleteId */);
testSingleDocument(
{_id: 0, a: {$slice: [1, 1]}}, {_id: 123, a: [1, 2, 3]}, {a: [2]}, false /* deleteId */);
})();
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