feat: Add transaction support. Passes transaction used by Models into…

… the plugin.
jarrodconnolly · Aug 27, 2020 · a1b726a · a1b726a
1 parent 50a6953
commit a1b726a
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Showing 3 changed files with 210 additions and 113 deletions.
diff --git a/README.md b/README.md
@@ -39,6 +39,7 @@ SequelizeSlugify.slugifyModel(User, {
     overwrite: false,
     column: 'slug',
     incrementalSeparator: '-',
+    passTransaction: true
 });
 ```
 Available Options
@@ -48,8 +49,8 @@ Available Options
 - `slugOptions` - (Optional)(Default `{lower: true}`) Pass additional options for slug generation as defined by [`sluglife`](https://github.com/jarrodconnolly/sluglife#options).
 - `overwrite` - (Optional)(Default `true`) Change the slug if the source fields change once the slug has already been built.
 - `column` - (Optional)(Default `slug`) Specify which column the slug is to be stored into in the model.
-- `incrementalSeparator` - (Default `-`) Specify the separator between the slug, and the duplicate count.
-
+- `incrementalSeparator` - (Optional)(Default `-`) Specify the separator between the slug, and the duplicate count.
+- `passTransaction` - (Optional)(Default `true`) Whether to pass an outer transaction, if one exists, to the plugin.
 ## Usage Examples
 
 ### Basic Usage
@@ -156,3 +157,12 @@ export default (sequelize, DataTypes) => {
     return User;
 };
 ```
+## Transactions
+
+A transaction wrapping operations on the Model will be passed by default to the internals of this plugin. 
+This behaviour can be modified using the `passTransaction` option described above.
+
+Internally this plugin only calls a `findOne` operation, passing the transaction to this may help in specific Isolation scenarios depending on your underlying database.
+
+Fields modified when creating/updating the slug will be rolled back even if we do not pass the transaction due to the nature of how hooks operate.
+
diff --git a/lib/sequelize-slugify.js b/lib/sequelize-slugify.js
@@ -16,12 +16,13 @@ class SequelizeSlugify {
     const DEFAULT_OPTIONS = {
       overwrite: true,
       column: 'slug',
-      incrementalSeparator: '-'
+      incrementalSeparator: '-',
+      passTransaction: true
     };
 
     const slugifyOptions = {...DEFAULT_OPTIONS, ...options};
 
-    const handleSlugify = async function (instance) {
+    const handleSlugify = async function (instance, sequelizeOptions) {
 
       // check if any of the fields used to build the slug have changed
       const changed = slugifyOptions.source.some(function (slugSourceField) {
@@ -50,24 +51,27 @@ class SequelizeSlugify {
         return instance;
       }
 
+      // obtain transaction if enabled
+      const transaction = (slugifyOptions.passTransaction === true) ? sequelizeOptions.transaction : null;
+
       // determine if the slug is unique
-      let isUnique = await isUniqueSlug(slugValue);
+      let isUnique = await isUniqueSlug(slugValue, transaction);
       if (isUnique) {
         instance[slugColumn] = slugValue;
         return instance;
       }
 
       // add on suffixes from the provided source suffixes
-      slugValue = await addSourceSuffix(instance, slugValue, slugifyOptions.suffixSource);
+      slugValue = await addSourceSuffix(instance, slugValue, slugifyOptions.suffixSource, transaction);
 
       // determine if the slug is unique
-      isUnique = await isUniqueSlug(slugValue);
+      isUnique = await isUniqueSlug(slugValue, transaction);
       if (isUnique) {
         instance[slugColumn] = slugValue;
         return instance;
       }
 
-      slugValue = await addNumericSuffix(slugValue);
+      slugValue = await addNumericSuffix(slugValue, transaction);
 
       instance[slugColumn] = slugValue;
       return instance;
@@ -87,15 +91,16 @@ class SequelizeSlugify {
       return slug(slugParts.join(' '), options);
     };
 
-    const isUniqueSlug = async function (slug) {
+    const isUniqueSlug = async function (slug, transaction) {
       const result = await model.findOne({
-        where: {[slugColumn]: slug }
+        where: {[slugColumn]: slug },
+        transaction: transaction
       });
       return result === null;
     };
 
     // optionally adding suffix's from other field values
-    const addSourceSuffix = async function (instance, slugValue, suffixFields) {
+    const addSourceSuffix = async function (instance, slugValue, suffixFields, transaction) {
       // return current slug if no suffix provided
       if (!suffixFields || !Array.isArray(suffixFields)) {
         return slugValue;
@@ -110,21 +115,21 @@ class SequelizeSlugify {
           suffixedSlug += `${slugifyOptions.incrementalSeparator}${newSlugSection}`;
         }
         // if the slug is now unique we can stop
-        const foundUnique = await isUniqueSlug(suffixedSlug);
+        const foundUnique = await isUniqueSlug(suffixedSlug, transaction);
         if(foundUnique) {
           break;
         }
       }
       return suffixedSlug;
     };
 
-    const addNumericSuffix = async function (slugValue) {
+    const addNumericSuffix = async function (slugValue, transaction) {
       let count = 1;
       let foundUnique = false;
       let suffixedSlug = '';
       while(!foundUnique) {
         suffixedSlug = `${slugValue}${slugifyOptions.incrementalSeparator}${count}`;
-        foundUnique = await isUniqueSlug(suffixedSlug);
+        foundUnique = await isUniqueSlug(suffixedSlug, transaction);
         count++;
       }
       return suffixedSlug;