@mongoosejs/double/examples.md

Double support for Mongoose

# Examples

## It ensures your numbers are always stored as doubles in MongoDB

```javascript
const schema = new mongoose.Schema({ val: Double });
const Model = mongoose.model('Double', schema);

const doc = new Model({ val: 41 });

// `doc.val` will be an object, not a number, but you can still use it as
// a number
assert.ok(doc.val instanceof mongoose.Types.Double);
assert.ok(doc.val instanceof Number);
assert.equal(typeof doc.val, 'object');

++doc.val;

return doc.save().
  then(function() {
    return Model.findOne({ val: { $type: 'double' } });
  }).
  then(function(doc) {
    assert.ok(doc);
    assert.equal(doc.val, 42);
  }).
  then(function() {
    return Model.findOne({ val: { $type: 'int' } });
  }).
  then(function(doc) {
    assert.ok(!doc);
  });
```

## It bypasses the MongoDB driver's integer coercion


This plugin is useful because the [MongoDB Node.js driver](https://www.npmjs.com/package/mongodb)
will store the JavaScript number `5.01` as a double, but it will store `5`
as an integer. There is currently no option to opt out of this behavior
in the MongoDB driver.


```javascript
const schema = new mongoose.Schema({ val: Number });
const Model = mongoose.model('Number', schema);

return Model.create([{ val: 5.01 }, { val: 5 }]).
  then(function() {
    return Model.findOne({ val: { $type: 'double' } });
  }).
  then(function(doc) {
    assert.ok(doc);
    assert.equal(doc.val, 5.01);
  }).
  then(function() {
    return Model.findOne({ val: { $type: 'int' } });
  }).
  then(function(doc) {
    assert.ok(doc);
    assert.equal(doc.val, 5);
  });
```