create own methods dynamically on chain steps

Signed-off-by: Tobias Gurtzick <magic@wizardtales.com>

Author: wzrdtales

lib/driver/shadow.js

@@ -57,6 +57,7 @@ exports.infect = function (db, intern, ShadowProto) {
 
 exports.overshadow = function (db, ShadowProto, ShadowError) {
   const newDb = Object.assign({}, ShadowProto);
+  newDb.prototype = Object.assign({}, ShadowProto.prototype);
 
   for (var prop in db) {
     if (

lib/learn.js

@@ -3,6 +3,15 @@ const Shadow = require('./driver/shadow');
 
 class STD {
   constructor ({ schema, modSchema: mod }, driver) {
+    this.checkColumn = function (t, c) {
+      if (!this.schema[t]) {
+        throw new Error(`There is no ${t} table in schema!`);
+      }
+
+      if (!this.schema[t][c]) {
+        throw new Error(`There is no ${c} column in schema!`);
+      }
+    };
     this.validations = {};
     this.driver = driver;
     this.indizies = schema.i;
@@ -97,60 +106,82 @@ class STD {
 
   removeColumn (t, c, o) {
     let alter = {};
-    if (this.schema[t]) {
-      if (this.schema[t][c].notNull === true) {
-        if (this.validations.columnStrategies !== true) {
-          if (
-            this.driver._meta &&
-            this.driver._meta.supports &&
-            this.driver._meta.supports.optionParam === true
-          ) {
-            /**
-             * This is a validation only, no action will be taken unless throwing
-             * errors.
-             *
-             * The driver needs to respect the options properly.
-             */
-            switch (o.columnStrategy) {
-              case 'defaultValue':
-                break;
-              case 'delay':
-                break;
-              default:
-                if (!o.columnStrategy) {
-                  throw new Error(
-                    'Can not drop a notNull column without providing a' +
-                      ' recreation strategy.'
-                  );
-                }
+    this.checkColumn(t, c);
+
+    if (this.schema[t][c].notNull === true) {
+      if (this.validations.columnStrategies !== true) {
+        if (
+          this.driver._meta &&
+          this.driver._meta.supports &&
+          this.driver._meta.supports.optionParam === true
+        ) {
+          /**
+           * This is a validation only, no action will be taken unless throwing
+           * errors.
+           *
+           * The driver needs to respect the options properly.
+           */
+          switch (o.columnStrategy) {
+            case 'defaultValue':
+              break;
+            case 'delay':
+              break;
+            default:
+              if (!o.columnStrategy) {
                 throw new Error(
-                  `There is no such column recreation strategy "${
-                    o.columnStrategy
-                  }!"`
+                  'Can not drop a notNull column without providing a' +
+                    ' recreation strategy.'
                 );
-            }
-          } else {
-            throw new Error(
-              'This driver does not support optionParameters which are' +
-                ' required to provide a recreation strategy.'
-            );
-          }
-
-          if (!this.driver._meta.supports.columnStrategies) {
-            throw new Error(
-              'This driver does not support column recreation strategies.'
-            );
+              }
+              throw new Error(
+                `There is no such column recreation strategy "${
+                  o.columnStrategy
+                }!"`
+              );
           }
+        } else {
+          throw new Error(
+            'This driver does not support optionParameters which are' +
+              ' required to provide a recreation strategy.'
+          );
+        }
 
-          this.validations.columnStrategies = true;
+        if (!this.driver._meta.supports.columnStrategies) {
+          throw new Error(
+            'This driver does not support column recreation strategies.'
+          );
         }
+
+        this.validations.columnStrategies = true;
       }
-      this.modS[t] = {};
-      this.modS[t][c] = this.schema[t][c];
-      delete this.schema[t][c];
     }
 
-    this.modC.push({ t: 1, a: 'addColumn', c: [t, c] });
+    this.modS[t] = {};
+
+    switch (o.columnStrategies) {
+      case 'delay':
+        this.modS[t][c] = this.schema[t][c];
+
+        o.passthrough = o.passthrough || {};
+        o.passthrough.column =
+          o.passthrough.column || `__dbmrn_${c}_${new Date().toString()}__`;
+
+        this.modC.push({
+          t: 1,
+          a: 'renameColumn',
+          c: [t, o.passthrough.column, c]
+        });
+
+        break;
+      case 'defaultValue':
+        this.modS[t][c] = this.schema[t][c];
+        this.modS[t][c].defaultValue = o.passthrough.defaultValue;
+
+        this.modC.push({ t: 1, a: 'addColumn', c: [t, c, o] });
+        break;
+    }
+
+    delete this.schema[t][c];
 
     return Promise.resolve(alter);
   }
@@ -178,16 +209,6 @@ class STD {
     return Promise.resolve();
   }
 
-  checkColumn (t, c) {
-    if (!this.schema[t]) {
-      throw new Error(`There is no ${t} table in schema!`);
-    }
-
-    if (!this.schema[t][c]) {
-      throw new Error(`There is no ${c} column in schema!`);
-    }
-  }
-
   changeColumn (t, c, s) {
     this.checkColumn(t, c);