mongo/jstests/core/query/array/array4.js

/**
 * Basic test for querying on documents containing arrays.
 *  @tags: [
 *    requires_getmore
 *  ]
 */
const collNamePrefix = "array4_";
let collCount = 0;

let t = db.getCollection(collNamePrefix + collCount++);
t.drop();

t.insert({_id: 0, "a": ["1", "2", "3"]});
t.insert({_id: 1, "a": ["2", "1"]});

let query = {"a.0": /1/};

let docs = t.find(query).toArray();
assert.eq(docs.length, 1, tojson(docs));

assert.eq(docs[0].a[0], 1, tojson(docs));
assert.eq(docs[0].a[1], 2, tojson(docs));

t = db.getCollection(collNamePrefix + collCount++);
t.drop();

t.insert({_id: 2, "a": {"0": "1"}});
t.insert({_id: 3, "a": ["2", "1"]});

docs = t.find(query).toArray();
assert.eq(docs.length, 1, tojson(docs));
assert.eq(docs[0].a[0], 1, tojson(docs));

t = db.getCollection(collNamePrefix + collCount++);
t.drop();

t.insert({_id: 4, "a": ["0", "1", "2", "3", "4", "5", "6", "1", "1", "1", "2", "3", "2", "1"]});
t.insert({_id: 5, "a": ["2", "1"]});

query = {
    "a.12": /2/,
};

docs = t.find(query).toArray();
assert.eq(docs.length, 1, tojson(docs));
assert.eq(docs[0].a[0], 0, tojson(docs));