DELETE request: only remove dependent document + add no cascade flag

README.md

@@ -97,6 +97,7 @@ Also when doing requests, it's good to know that:
 - Your request body JSON should be object enclosed, just like the GET output. (for example `{"name": "Foobar"}`)
 - Id values are not mutable. Any `id` value in the body of your PUT or PATCH request wil be ignored. Only a value set in a POST request wil be respected, but only if not already taken.
 - A POST, PUT or PATCH request should include a `Content-Type: application/json` header to use the JSON in the request body. Otherwise it will result in a 200 OK but without changes being made to the data.
+- DELETE requests will look for dependent documents, and will remove them as well. That means that for the previous `db.json` file, a `DELETE /posts/1` would also delete the dependent comment (with `postId: 1`). You can disable this behavior by raising the 'no-delete-cascade' flag. See [CLI usage](#cli-usage).
 
 ## Install
 
@@ -369,6 +370,7 @@ Options:
   --static, -s       Set static files directory
   --read-only, --ro  Allow only GET requests                           [boolean]
   --no-cors, --nc    Disable Cross-Origin Resource Sharing             [boolean]
+  --no-delete-cascade, --ndc    Disable delete cacade behavior         [boolean]
   --no-gzip, --ng    Disable GZIP Content-Encoding                     [boolean]
   --snapshots, -S    Set snapshots directory                      [default: "."]
   --delay, -d        Add delay to responses (ms)

src/cli/index.js

@@ -45,6 +45,10 @@ module.exports = function() {
         alias: 'nc',
         description: 'Disable Cross-Origin Resource Sharing'
       },
+      'no-delete-cascade': {
+        alias: 'ndc',
+        description: 'Disable delete cascade behavior'
+      },
       'no-gzip': {
         alias: 'ng',
         description: 'Disable GZIP Content-Encoding'
@@ -82,6 +86,7 @@ module.exports = function() {
     .boolean('read-only')
     .boolean('quiet')
     .boolean('no-cors')
+    .boolean('no-delete-cascade')
     .boolean('no-gzip')
     .help('help')
     .alias('help', 'h')

src/cli/run.js

@@ -40,12 +40,12 @@ function createApp(source, object, routes, middlewares, argv) {
 
   let router
 
-  const { foreignKeySuffix } = argv
+  const { foreignKeySuffix, noDeleteCascade } = argv
   try {
-    router = jsonServer.router(
-      is.JSON(source) ? source : object,
-      foreignKeySuffix ? { foreignKeySuffix } : undefined
-    )
+    router = jsonServer.router(is.JSON(source) ? source : object, {
+      foreignKeySuffix,
+      noDeleteCascade
+    })
   } catch (e) {
     console.log()
     console.error(chalk.red(e.message.replace(/^/gm, '  ')))

src/server/mixins.js

@@ -1,40 +1,38 @@
 const nanoid = require('nanoid')
-const pluralize = require('pluralize')
 
 module.exports = {
-  getRemovable,
+  getDependents,
   createId,
   deepQuery
 }
 
-// Returns document ids that have unsatisfied relations
-// Example: a comment that references a post that doesn't exist
-function getRemovable(db, opts) {
+/**
+ * Return documents which are dependent on the specified foreign field
+ * Example: a comment that references a post that doesn't exist
+ *
+ * @param {object} db - The entire database object
+ * @param {string} foreignField - The foreign field name. e.g. "postId"
+ * @param {string|number} foreignId - The foreign field id to match
+ * @return {[{name: string, id: string|number]} - Array of dependent objects with resource names and ids
+ */
+function getDependents(db, foreignField, foreignId) {
   const _ = this
-  const removable = []
-  _.each(db, (coll, collName) => {
-    _.each(coll, doc => {
-      _.each(doc, (value, key) => {
-        if (new RegExp(`${opts.foreignKeySuffix}$`).test(key)) {
-          // Remove foreign key suffix and pluralize it
-          // Example postId -> posts
-          const refName = pluralize.plural(
-            key.replace(new RegExp(`${opts.foreignKeySuffix}$`), '')
-          )
-          // Test if table exists
-          if (db[refName]) {
-            // Test if references is defined in table
-            const ref = _.getById(db[refName], value)
-            if (_.isUndefined(ref)) {
-              removable.push({ name: collName, id: doc.id })
-            }
-          }
-        }
-      })
-    })
-  })
-
-  return removable
+  return _.reduce(
+    db,
+    (acc, table, tableName) =>
+      // only work on arrays; object are irrelevant
+      !_.isArray(table)
+        ? acc
+        : table
+            .filter(
+              doc =>
+                // perform a type-insensitive comparison (so we could compare '2' to 2
+                _.get(doc, foreignField, '').toString() === foreignId.toString()
+            )
+            .map(doc => ({ name: tableName, id: doc.id }))
+            .concat(acc),
+    []
+  )
 }
 
 // Return incremented id or uuid

src/server/router/index.js

@@ -65,11 +65,8 @@ module.exports = (source, opts = { foreignKeySuffix: 'Id' }) => {
         return
       }
 
-      const msg =
-        `Type of "${key}" (${typeof value}) ${_.isObject(source)
-          ? ''
-          : `in ${source}`} is not supported. ` +
-        `Use objects or arrays of objects.`
+      const srcDesc = _.isObject(source) ? '' : `in ${source}`
+      const msg = `Type of "${key}" (${typeof value}) ${srcDesc} is not supported. Use objects or arrays of objects.`
 
       throw new Error(msg)
     })

src/server/router/plural.js

@@ -296,14 +296,17 @@ module.exports = (db, name, opts) => {
       .removeById(req.params.id)
       .value()
 
-    // Remove dependents documents
-    const removable = db._.getRemovable(db.getState(), opts)
-    removable.forEach(item => {
-      db
-        .get(item.name)
-        .removeById(item.id)
-        .value()
-    })
+    if (!opts.noDeleteCascade) {
+      // Remove dependents documents
+      const prop = `${pluralize.singular(name)}${opts.foreignKeySuffix}`
+      const dependents = db._.getDependents(db.getState(), prop, req.params.id)
+      dependents.forEach(item => {
+        db
+          .get(item.name)
+          .removeById(item.id)
+          .value()
+      })
+    }
 
     if (resource) {
       res.locals.data = {}

test/server/mixins.js

@@ -24,23 +24,28 @@ describe('mixins', () => {
     }
   })
 
-  describe('getRemovable', () => {
-    it('should return removable documents', () => {
+  describe('getDependents', () => {
+    it('should return dependent documents', () => {
       const expected = [
         { name: 'comments', id: 2 },
         { name: 'comments', id: 3 }
       ]
 
-      assert.deepEqual(_.getRemovable(db, { foreignKeySuffix: 'Id' }), expected)
+      assert.deepEqual(_.getDependents(db, 'postId', 2), expected)
     })
 
-    it('should support custom foreignKeySuffix', () => {
+    it('should return dependent documents (type insensitive)', () => {
       const expected = [
         { name: 'comments', id: 2 },
         { name: 'comments', id: 3 }
       ]
 
-      assert.deepEqual(_.getRemovable(db, { foreignKeySuffix: 'Id' }), expected)
+      assert.deepEqual(_.getDependents(db, 'postId', '2'), expected)
+    })
+
+    it('should not return irrelevant dead documents', () => {
+      const expected = [{ name: 'comments', id: 1 }]
+      assert.deepEqual(_.getDependents(db, 'postId', 1), expected)
     })
   })