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// In SERVER-10689, the $switch expression was introduced. In this file, we test the functionality
// of the expression.
(function() {
"use strict";
var coll = db.switch;
coll.drop();
// Insert an empty document so that something can flow through the pipeline.
coll.insert({});
// Ensure that a branch is correctly evaluated.
var pipeline = {
"$project": {
"_id": 0,
"output": {
"$switch": {
"branches": [{"case": {"$eq": [1, 1]}, "then": "one is equal to one!"}],
}
}
}
};
var res = coll.aggregate(pipeline).toArray();
assert.eq(res.length, 1);
assert.eq(res[0], {"output": "one is equal to one!"});
// Ensure that the first branch which matches is chosen.
pipeline = {
"$project": {
"_id": 0,
"output": {
"$switch": {
"branches": [
{"case": {"$eq": [1, 1]}, "then": "one is equal to one!"},
{"case": {"$eq": [2, 2]}, "then": "two is equal to two!"}
],
}
}
}
};
res = coll.aggregate(pipeline).toArray();
assert.eq(res.length, 1);
assert.eq(res[0], {"output": "one is equal to one!"});
// Ensure that the default is chosen if no case matches.
pipeline = {
"$project": {
"_id": 0,
"output": {
"$switch": {
"branches": [{"case": {"$eq": [1, 2]}, "then": "one is equal to two!"}],
"default": "no case matched."
}
}
}
};
res = coll.aggregate(pipeline).toArray();
assert.eq(res.length, 1);
assert.eq(res[0], {"output": "no case matched."});
// Ensure that nullish values are treated as false when they are a "case", and are null
// otherwise.
pipeline = {
"$project": {
"_id": 0,
"output": {
"$switch": {
"branches": [{"case": null, "then": "Null was true!"}],
"default": "No case matched."
}
}
}
};
res = coll.aggregate(pipeline).toArray();
assert.eq(res.length, 1);
assert.eq(res[0], {"output": "No case matched."});
pipeline = {
"$project": {
"_id": 0,
"output": {
"$switch": {
"branches": [{"case": "$missingField", "then": "Null was true!"}],
"default": "No case matched."
}
}
}
};
res = coll.aggregate(pipeline).toArray();
assert.eq(res.length, 1);
assert.eq(res[0], {"output": "No case matched."});
pipeline = {
"$project": {
"_id": 0,
"output": {"$switch": {"branches": [{"case": true, "then": null}], "default": false}}
}
};
res = coll.aggregate(pipeline).toArray();
assert.eq(res.length, 1);
assert.eq(res[0], {"output": null});
pipeline = {
"$project": {
"_id": 0,
"output": {
"$switch":
{"branches": [{"case": true, "then": "$missingField"}], "default": false}
}
}
};
res = coll.aggregate(pipeline).toArray();
assert.eq(res.length, 1);
assert.eq(res[0], {});
pipeline = {
"$project": {
"_id": 0,
"output": {"$switch": {"branches": [{"case": null, "then": false}], "default": null}}
}
};
res = coll.aggregate(pipeline).toArray();
assert.eq(res.length, 1);
assert.eq(res[0], {"output": null});
pipeline = {
"$project": {
"_id": 0,
"output": {
"$switch":
{"branches": [{"case": null, "then": false}], "default": "$missingField"}
}
}
};
res = coll.aggregate(pipeline).toArray();
assert.eq(res.length, 1);
assert.eq(res[0], {});
}());
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