feat(model): implement static first and last

first and last returns model instance for the first and the last row

src/Lucid/Model/index.js

@@ -691,6 +691,24 @@ class Model {
     return yield this.query().pair(lhs, rhs)
   }
 
+  /**
+   * Return the first row from the database
+   *
+   * @returns {Object}
+   */
+  static first () {
+    return this.query().first()
+  }
+
+  /**
+   * Return the last row from the database
+   *
+   * @returns {Object}
+   */
+  static last () {
+    return this.query().last()
+  }
+
   /**
    * truncate model database table
    *

src/Lucid/QueryBuilder/methods.js

@@ -165,6 +165,22 @@ methods.first = function (target) {
   }
 }
 
+/**
+ * Returns the last record from the data collection
+ *
+ * @param  {Object} target
+ * @return {Object}
+ *
+ * @public
+ */
+methods.last = function (target) {
+  return function * () {
+    target.modelQueryBuilder.orderBy(target.HostModel.primaryKey, 'desc').limit(1)
+    const results = yield this.fetch()
+    return results.first() || null
+  }
+}
+
 /**
  * returns the first record from data collection
  * or fails by throwing an exception

test/unit/lucid.spec.js

@@ -2143,5 +2143,33 @@ describe('Lucid', function () {
       User.bootIfNotBooted()
       expect(User.findByTrait).to.be.a('function')
     })
+
+    it('should return the first row from the database as model instance', function * () {
+      let query = null
+      class User extends Model {
+        static boot () {
+          super.boot()
+          this.onQuery((q) => { query = q })
+        }
+      }
+      User.bootIfNotBooted()
+      yield User.first()
+      expect(queryHelpers.formatQuery(query.sql)).to.equal(queryHelpers.formatQuery('select * from "users" limit ?'))
+      expect(queryHelpers.formatBindings(query.bindings)).deep.equal(queryHelpers.formatBindings([1]))
+    })
+
+    it('should return the last row from the database as model instance', function * () {
+      let query = null
+      class User extends Model {
+        static boot () {
+          super.boot()
+          this.onQuery((q) => { query = q })
+        }
+      }
+      User.bootIfNotBooted()
+      yield User.last()
+      expect(queryHelpers.formatQuery(query.sql)).to.equal(queryHelpers.formatQuery('select * from "users" order by "id" desc limit ?'))
+      expect(queryHelpers.formatBindings(query.bindings)).deep.equal(queryHelpers.formatBindings([1]))
+    })
   })
 })