lib: Replace lodash/isEmpty with a custom function

Author: nwoltman

lib/PoolPlus.js

@@ -12,14 +12,22 @@ const PoolConfig = require('mysql/lib/PoolConfig');
 const SqlString = require('mysql/lib/protocol/SqlString');
 const TableDefinition = require('./TableDefinition');
 
-const isEmpty = require('lodash/isEmpty');
-
 const MIGRATION_STRATEGIES = [
   'safe',
   'alter',
   'drop',
 ];
 
+function isObjectEmpty(obj) {
+  for (var key in obj) {
+    if (!obj.hasOwnProperty || obj.hasOwnProperty(key)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
 function validateMigrationStrategy(strategy) {
   if (strategy && MIGRATION_STRATEGIES.indexOf(strategy) < 0) {
     throw new Error(`"${strategy}" is not a valid migration strategy`);
@@ -97,7 +105,7 @@ class PoolPlus extends Pool {
     if (this._tables.has(name)) {
       throw new Error(`A table called "${name}" has already been defined for this pool`);
     }
-    if (isEmpty(schema.columns)) {
+    if (isObjectEmpty(schema.columns)) {
       throw new Error('The schema must have at least one table column');
     }
     validateMigrationStrategy(migrationStrategy);

test/unit/PoolPlus.test.js

@@ -110,6 +110,12 @@ describe('PoolPlus', () => {
     it('should throw if no columns are provided', () => {
       should.throws(() => pool.defineTable('table', {}), /must have.*column/);
       should.throws(() => pool.defineTable('table', {columns: {}}), /must have.*column/);
+      should.throws(() => pool.defineTable('table', {columns: Object.create(null)}), /must have.*column/);
+
+      function Clazz() { /* constructor */ }
+      Clazz.prototype.foo = 1; // So the instance will have enumerable properties but no "own" properties
+
+      should.throws(() => pool.defineTable('table', {columns: new Clazz()}), /must have.*column/);
     });
 
     it('should throw if the specified migration strategy is invalid', () => {