refactor(relationships): Use contants instead of magic strings

Author: digitalsadhu

lib/utilities/relationship-utils.js

@@ -4,6 +4,13 @@ var _ = require('lodash')
 var statusCodes = require('http-status-codes')
 const utils = require('../utils')
 
+const RELATION_TYPES = Object.freeze({
+  HAS_MANY_THROUGH: 0,
+  HAS_MANY: 1,
+  HAS_ONE: 2,
+  BELONGS_TO: 3
+})
+
 /* global module */
 module.exports = {
   getIncludesArray: getIncludesArray,
@@ -170,17 +177,17 @@ function updateHasManyThrough (
 
 function detectUpdateStrategy (Model, relationName) {
   const relationDefn = Model.relations[relationName]
-  if (relationDefn.modelThrough) return 'updateHasManyThrough'
-  if (relationDefn.type === 'hasMany') return 'updateHasMany'
-  if (relationDefn.type === 'hasOne') return 'updateHasOne'
-  if (relationDefn.type === 'belongsTo') return 'updateBelongsTo'
+  if (relationDefn.modelThrough) return RELATION_TYPES.HAS_MANY_THROUGH
+  if (relationDefn.type === 'hasMany') return RELATION_TYPES.HAS_MANY
+  if (relationDefn.type === 'hasOne') return RELATION_TYPES.HAS_ONE
+  if (relationDefn.type === 'belongsTo') return RELATION_TYPES.BELONGS_TO
 }
 
 function linkRelatedModels (relationName, LeftModel, id, RightModel, data) {
   const relationDefn = LeftModel.relations[relationName]
   const strategy = detectUpdateStrategy(LeftModel, relationName)
 
-  if (strategy === 'updateHasManyThrough') {
+  if (strategy === RELATION_TYPES.HAS_MANY_THROUGH) {
     const leftPrimaryKey = utils.primaryKeyForModel(LeftModel)
     const rightPrimaryKey = utils.primaryKeyForModel(RightModel)
     const PivotModel = relationDefn.modelThrough
@@ -197,19 +204,19 @@ function linkRelatedModels (relationName, LeftModel, id, RightModel, data) {
     )
   }
 
-  if (strategy === 'updateHasMany') {
+  if (strategy === RELATION_TYPES.HAS_MANY) {
     const leftPrimaryKey = utils.primaryKeyForModel(LeftModel)
     const rightForeignKey = relationDefn.keyTo
     return updateHasMany(leftPrimaryKey, id, RightModel, rightForeignKey, data)
   }
 
-  if (strategy === 'updateHasOne') {
+  if (strategy === RELATION_TYPES.HAS_ONE) {
     const rightPrimaryKey = utils.primaryKeyForModel(RightModel)
     const rightForeignKey = relationDefn.keyTo
     return updateHasOne(rightPrimaryKey, id, RightModel, rightForeignKey, data)
   }
 
-  if (strategy === 'updateBelongsTo') {
+  if (strategy === RELATION_TYPES.BELONGS_TO) {
     const leftPrimaryKey = utils.primaryKeyForModel(LeftModel)
     const leftForeignKey = relationDefn.keyFrom
     return updateBelongsTo(LeftModel, leftPrimaryKey, id, leftForeignKey, data)

test/config.test.js

@@ -1,3 +1,5 @@
+'use strict'
+
 var request = require('supertest')
 var loopback = require('loopback')
 var expect = require('chai').expect

test/relationship-utils.test.js

@@ -241,23 +241,21 @@ describe('relationship utils', () => {
   })
 
   describe('detectUpdateStrategy()', function () {
+    it('hasManyThrough', () => {
+      setupHasManyThrough()
+      expect(detectUpdateStrategy(Post, 'comments')).to.equal(0)
+    })
     it('hasMany', () => {
       setupHasMany()
-      expect(detectUpdateStrategy(Post, 'comments')).to.equal('updateHasMany')
-    })
-    it('belongsTo', () => {
-      setupBelongsTo()
-      expect(detectUpdateStrategy(Comment, 'post')).to.equal('updateBelongsTo')
+      expect(detectUpdateStrategy(Post, 'comments')).to.equal(1)
     })
     it('hasOne', () => {
       setupHasOne()
-      expect(detectUpdateStrategy(Post, 'comment')).to.equal('updateHasOne')
+      expect(detectUpdateStrategy(Post, 'comment')).to.equal(2)
     })
-    it('hasManyThrough', () => {
-      setupHasManyThrough()
-      expect(detectUpdateStrategy(Post, 'comments')).to.equal(
-        'updateHasManyThrough'
-      )
+    it('belongsTo', () => {
+      setupBelongsTo()
+      expect(detectUpdateStrategy(Comment, 'post')).to.equal(3)
     })
   })
 })