diff --git a/.eslintignore b/.eslintignore
index abe1141d33..c42969499c 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -2,12 +2,11 @@
 
 /packages/medusa/src/services/cart.js
 /packages/medusa/src/services/claim-item.js
-/packages/medusa/src/services/claim.js
 /packages/medusa/src/services/customer.js
-/packages/medusa/src/services/discount.js
 /packages/medusa/src/services/draft-order.js
 /packages/medusa/src/services/event-bus.js
 /packages/medusa/src/services/fulfillment.js
+/packages/medusa/src/services/fulfillment-provider.js
 /packages/medusa/src/services/idempotency-key.js
 /packages/medusa/src/services/line-item.js
 /packages/medusa/src/services/middleware.js
diff --git a/packages/medusa/src/services/claim.js b/packages/medusa/src/services/claim.js
index 9d60a28626..8e73dbf83e 100644
--- a/packages/medusa/src/services/claim.js
+++ b/packages/medusa/src/services/claim.js
@@ -1,7 +1,5 @@
-import _ from "lodash"
-import { Validator, MedusaError } from "medusa-core-utils"
+import { MedusaError } from "medusa-core-utils"
 import { BaseService } from "medusa-interfaces"
-import { Brackets } from "typeorm"
 
 class ClaimService extends BaseService {
   static Events = {
@@ -102,7 +100,7 @@ class ClaimService extends BaseService {
   }
 
   update(id, data) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const claimRepo = manager.getCustomRepository(this.claimRepository_)
       const claim = await this.retrieve(id, { relations: ["shipping_methods"] })
 
@@ -113,13 +111,7 @@ class ClaimService extends BaseService {
         )
       }
 
-      const {
-        claim_items,
-        shipping_methods,
-        metadata,
-        fulfillment_status,
-        no_notification,
-      } = data
+      const { claim_items, shipping_methods, metadata, no_notification } = data
 
       if (metadata) {
         claim.metadata = this.setMetadata_(claim, metadata)
@@ -183,9 +175,11 @@ class ClaimService extends BaseService {
    * Creates a Claim on an Order. Claims consists of items that are claimed and
    * optionally items to be sent as replacement for the claimed items. The
    * shipping address that the new items will be shipped to
+   * @param {Object} data - the object containing all data required to create a claim
+   * @return {Object} created claim
    */
   create(data) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const claimRepo = manager.getCustomRepository(this.claimRepository_)
 
       const {
@@ -257,8 +251,8 @@ class ClaimService extends BaseService {
 
       let toRefund = refund_amount
       if (type === "refund" && typeof refund_amount === "undefined") {
-        const lines = claim_items.map(ci => {
-          const orderItem = order.items.find(oi => oi.id === ci.item_id)
+        const lines = claim_items.map((ci) => {
+          const orderItem = order.items.find((oi) => oi.id === ci.item_id)
           return {
             ...orderItem,
             quantity: ci.quantity,
@@ -274,7 +268,7 @@ class ClaimService extends BaseService {
       }
 
       const newItems = await Promise.all(
-        additional_items.map(i =>
+        additional_items.map((i) =>
           this.lineItemService_
             .withTransaction(manager)
             .generate(i.variant_id, order.region_id, i.quantity)
@@ -332,7 +326,7 @@ class ClaimService extends BaseService {
         await this.returnService_.withTransaction(manager).create({
           order_id: order.id,
           claim_order_id: result.id,
-          items: claim_items.map(ci => ({
+          items: claim_items.map((ci) => ({
             item_id: ci.item_id,
             quantity: ci.quantity,
             metadata: ci.metadata,
@@ -362,7 +356,7 @@ class ClaimService extends BaseService {
   ) {
     const { metadata, no_notification } = config
 
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const claim = await this.retrieve(id, {
         relations: [
           "additional_items",
@@ -429,7 +423,7 @@ class ClaimService extends BaseService {
             is_claim: true,
             no_notification: evaluatedNoNotification,
           },
-          claim.additional_items.map(i => ({
+          claim.additional_items.map((i) => ({
             item_id: i.id,
             quantity: i.quantity,
           })),
@@ -445,7 +439,7 @@ class ClaimService extends BaseService {
 
       for (const item of claim.additional_items) {
         const fulfillmentItem = successfullyFulfilled.find(
-          f => item.id === f.item_id
+          (f) => item.id === f.item_id
         )
 
         if (fulfillmentItem) {
@@ -485,7 +479,7 @@ class ClaimService extends BaseService {
   }
 
   async cancelFulfillment(fulfillmentId) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const canceled = await this.fulfillmentService_
         .withTransaction(manager)
         .cancelFulfillment(fulfillmentId)
@@ -508,7 +502,7 @@ class ClaimService extends BaseService {
   }
 
   async processRefund(id) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const claim = await this.retrieve(id, {
         relations: ["order", "order.payments"],
       })
@@ -560,7 +554,7 @@ class ClaimService extends BaseService {
   ) {
     const { metadata, no_notification } = config
 
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const claim = await this.retrieve(id, {
         relations: ["additional_items"],
       })
@@ -584,7 +578,7 @@ class ClaimService extends BaseService {
       claim.fulfillment_status = "shipped"
 
       for (const i of claim.additional_items) {
-        const shipped = shipment.items.find(si => si.item_id === i.id)
+        const shipped = shipment.items.find((si) => si.item_id === i.id)
         if (shipped) {
           const shippedQty = (i.shipped_quantity || 0) + shipped.quantity
           await this.lineItemService_.withTransaction(manager).update(i.id, {
@@ -617,7 +611,7 @@ class ClaimService extends BaseService {
   }
 
   async cancel(id) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const claim = await this.retrieve(id, {
         relations: ["return_order", "fulfillments", "order", "order.refunds"],
       })
@@ -665,6 +659,7 @@ class ClaimService extends BaseService {
 
   /**
    * @param {Object} selector - the query object for find
+   * @param {Object} config - the config object containing query settings
    * @return {Promise} the result of the find operation
    */
   async list(
@@ -678,7 +673,8 @@ class ClaimService extends BaseService {
 
   /**
    * Gets an order by id.
-   * @param {string} orderId - id of order to retrieve
+   * @param {string} claimId - id of order to retrieve
+   * @param {Object} config - the config object containing query settings
    * @return {Promise<Order>} the order document
    */
   async retrieve(claimId, config = {}) {
@@ -717,7 +713,7 @@ class ClaimService extends BaseService {
     const keyPath = `metadata.${key}`
     return this.orderModel_
       .updateOne({ _id: validatedId }, { $unset: { [keyPath]: "" } })
-      .catch(err => {
+      .catch((err) => {
         throw new MedusaError(MedusaError.Types.DB_ERROR, err.message)
       })
   }
diff --git a/packages/medusa/src/services/discount.js b/packages/medusa/src/services/discount.js
index 70f404f378..bb796208ce 100644
--- a/packages/medusa/src/services/discount.js
+++ b/packages/medusa/src/services/discount.js
@@ -1,14 +1,11 @@
-import _ from "lodash"
-import randomize from "randomatic"
 import { BaseService } from "medusa-interfaces"
 import { Validator, MedusaError } from "medusa-core-utils"
-import { MedusaErrorCodes } from "medusa-core-utils/dist/errors"
 import { parse, toSeconds } from "iso8601-duration"
 import { Brackets, ILike } from "typeorm"
 
 /**
  * Provides layer to manipulate discounts.
- * @implements BaseService
+ * @implements {BaseService}
  */
 class DiscountService extends BaseService {
   constructor({
@@ -17,7 +14,6 @@ class DiscountService extends BaseService {
     discountRuleRepository,
     giftCardRepository,
     totalsService,
-    productVariantService,
     productService,
     regionService,
     eventBusService,
@@ -80,21 +76,13 @@ class DiscountService extends BaseService {
       id: Validator.string().optional(),
       description: Validator.string().optional(),
       type: Validator.string().required(),
-      value: Validator.number()
-        .min(0)
-        .required(),
+      value: Validator.number().min(0).required(),
       allocation: Validator.string().required(),
       valid_for: Validator.array().optional(),
       created_at: Validator.date().optional(),
-      updated_at: Validator.date()
-        .allow(null)
-        .optional(),
-      deleted_at: Validator.date()
-        .allow(null)
-        .optional(),
-      metadata: Validator.object()
-        .allow(null)
-        .optional(),
+      updated_at: Validator.date().allow(null).optional(),
+      deleted_at: Validator.date().allow(null).optional(),
+      metadata: Validator.object().allow(null).optional(),
     })
 
     const { value, error } = schema.validate(discountRule)
@@ -117,6 +105,7 @@ class DiscountService extends BaseService {
 
   /**
    * @param {Object} selector - the query object for find
+   * @param {Object} config - the config object containing query settings
    * @return {Promise} the result of the find operation
    */
   async list(selector = {}, config = { relations: [], skip: 0, take: 10 }) {
@@ -130,6 +119,7 @@ class DiscountService extends BaseService {
 
   /**
    * @param {Object} selector - the query object for find
+   * @param {Object} config - the config object containing query settings
    * @return {Promise} the result of the find operation
    */
   async listAndCount(
@@ -153,11 +143,11 @@ class DiscountService extends BaseService {
 
       delete where.code
 
-      query.where = qb => {
+      query.where = (qb) => {
         qb.where(where)
 
         qb.andWhere(
-          new Brackets(qb => {
+          new Brackets((qb) => {
             qb.where({ code: ILike(`%${q}%`) })
           })
         )
@@ -176,19 +166,19 @@ class DiscountService extends BaseService {
    * @return {Promise} the result of the create operation
    */
   async create(discount) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const discountRepo = manager.getCustomRepository(this.discountRepository_)
       const ruleRepo = manager.getCustomRepository(this.discountRuleRepository_)
 
       if (discount.rule?.valid_for) {
-        discount.rule.valid_for = discount.rule.valid_for.map(id => ({ id }))
+        discount.rule.valid_for = discount.rule.valid_for.map((id) => ({ id }))
       }
 
       const validatedRule = this.validateDiscountRule_(discount.rule)
 
       if (discount.regions) {
         discount.regions = await Promise.all(
-          discount.regions.map(regionId =>
+          discount.regions.map((regionId) =>
             this.regionService_.withTransaction(manager).retrieve(regionId)
           )
         )
@@ -209,6 +199,7 @@ class DiscountService extends BaseService {
   /**
    * Gets a discount by id.
    * @param {string} discountId - id of discount to retrieve
+   * @param {Object} config - the config object containing query settings
    * @return {Promise<Discount>} the discount
    */
   async retrieve(discountId, config = {}) {
@@ -233,6 +224,7 @@ class DiscountService extends BaseService {
   /**
    * Gets a discount by discount code.
    * @param {string} discountCode - discount code of discount to retrieve
+   * @param {array} relations - list of relations
    * @return {Promise<Discount>} the discount document
    */
   async retrieveByCode(discountCode, relations = []) {
@@ -269,7 +261,7 @@ class DiscountService extends BaseService {
    * @return {Promise} the result of the update operation
    */
   async update(discountId, update) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const discountRepo = manager.getCustomRepository(this.discountRepository_)
 
       const discount = await this.retrieve(discountId)
@@ -287,7 +279,7 @@ class DiscountService extends BaseService {
 
       if (regions) {
         discount.regions = await Promise.all(
-          regions.map(regionId => this.regionService_.retrieve(regionId))
+          regions.map((regionId) => this.regionService_.retrieve(regionId))
         )
       }
 
@@ -298,7 +290,9 @@ class DiscountService extends BaseService {
       if (rule) {
         discount.rule = this.validateDiscountRule_(rule)
         if (rule.valid_for) {
-          discount.rule.valid_for = discount.rule.valid_for.map(id => ({ id }))
+          discount.rule.valid_for = discount.rule.valid_for.map((id) => ({
+            id,
+          }))
         }
       }
 
@@ -314,11 +308,11 @@ class DiscountService extends BaseService {
   /**
    * Creates a dynamic code for a discount id.
    * @param {string} discountId - the id of the discount to create a code for
-   * @param {string} code - the code to identify the discount by
+   * @param {Object} data - the object containing a code to identify the discount by
    * @return {Promise} the newly created dynamic code
    */
   async createDynamicCode(discountId, data) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const discountRepo = manager.getCustomRepository(this.discountRepository_)
 
       const discount = await this.retrieve(discountId)
@@ -367,13 +361,15 @@ class DiscountService extends BaseService {
    * @return {Promise} the newly created dynamic code
    */
   async deleteDynamicCode(discountId, code) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const discountRepo = manager.getCustomRepository(this.discountRepository_)
       const discount = await discountRepo.findOne({
         where: { parent_discount_id: discountId, code },
       })
 
-      if (!discount) return Promise.resolve()
+      if (!discount) {
+        return Promise.resolve()
+      }
 
       await discountRepo.softRemove(discount)
 
@@ -388,7 +384,7 @@ class DiscountService extends BaseService {
    * @return {Promise} the result of the update operation
    */
   async addValidProduct(discountId, productId) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const discountRuleRepo = manager.getCustomRepository(
         this.discountRuleRepository_
       )
@@ -399,7 +395,7 @@ class DiscountService extends BaseService {
 
       const { rule } = discount
 
-      const exists = rule.valid_for.find(p => p.id === productId)
+      const exists = rule.valid_for.find((p) => p.id === productId)
       // If product is already present, we return early
       if (exists) {
         return rule
@@ -421,7 +417,7 @@ class DiscountService extends BaseService {
    * @return {Promise} the result of the update operation
    */
   async removeValidProduct(discountId, productId) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const discountRuleRepo = manager.getCustomRepository(
         this.discountRuleRepository_
       )
@@ -432,13 +428,13 @@ class DiscountService extends BaseService {
 
       const { rule } = discount
 
-      const exists = rule.valid_for.find(p => p.id === productId)
+      const exists = rule.valid_for.find((p) => p.id === productId)
       // If product is not present, we return early
       if (!exists) {
         return rule
       }
 
-      rule.valid_for = rule.valid_for.filter(p => p.id !== productId)
+      rule.valid_for = rule.valid_for.filter((p) => p.id !== productId)
 
       const updated = await discountRuleRepo.save(rule)
       return updated
@@ -452,14 +448,14 @@ class DiscountService extends BaseService {
    * @return {Promise} the result of the update operation
    */
   async addRegion(discountId, regionId) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const discountRepo = manager.getCustomRepository(this.discountRepository_)
 
       const discount = await this.retrieve(discountId, {
         relations: ["regions"],
       })
 
-      const exists = discount.regions.find(r => r.id === regionId)
+      const exists = discount.regions.find((r) => r.id === regionId)
       // If region is already present, we return early
       if (exists) {
         return discount
@@ -481,20 +477,20 @@ class DiscountService extends BaseService {
    * @return {Promise} the result of the update operation
    */
   async removeRegion(discountId, regionId) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const discountRepo = manager.getCustomRepository(this.discountRepository_)
 
       const discount = await this.retrieve(discountId, {
         relations: ["regions"],
       })
 
-      const exists = discount.regions.find(r => r.id === regionId)
+      const exists = discount.regions.find((r) => r.id === regionId)
       // If region is not present, we return early
       if (!exists) {
         return discount
       }
 
-      discount.regions = discount.regions.filter(r => r.id !== regionId)
+      discount.regions = discount.regions.filter((r) => r.id !== regionId)
 
       const updated = await discountRepo.save(discount)
       return updated
@@ -507,12 +503,14 @@ class DiscountService extends BaseService {
    * @return {Promise} the result of the delete operation
    */
   async delete(discountId) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const discountRepo = manager.getCustomRepository(this.discountRepository_)
 
       const discount = await discountRepo.findOne({ where: { id: discountId } })
 
-      if (!discount) return Promise.resolve()
+      if (!discount) {
+        return Promise.resolve()
+      }
 
       await discountRepo.softRemove(discount)
 
@@ -522,7 +520,7 @@ class DiscountService extends BaseService {
 
   /**
    * Decorates a discount.
-   * @param {Discount} discount - the discount to decorate.
+   * @param {string} discountId -  id of discount to decorate
    * @param {string[]} fields - the fields to include.
    * @param {string[]} expandFields - fields to expand.
    * @return {Discount} return the decorated discount.
diff --git a/packages/medusa/src/services/fulfillment.js b/packages/medusa/src/services/fulfillment.js
index ed0b4e4f80..b2cd6b71bc 100644
--- a/packages/medusa/src/services/fulfillment.js
+++ b/packages/medusa/src/services/fulfillment.js
@@ -1,10 +1,9 @@
-import _ from "lodash"
 import { BaseService } from "medusa-interfaces"
 import { MedusaError } from "medusa-core-utils"
 
 /**
  * Handles Fulfillments
- * @implements BaseService
+ * @extends BaseService
  */
 class FulfillmentService extends BaseService {
   constructor({
@@ -61,7 +60,7 @@ class FulfillmentService extends BaseService {
   }
 
   partitionItems_(shippingMethods, items) {
-    let partitioned = []
+    const partitioned = []
     // partition order items to their dedicated shipping method
     for (const method of shippingMethods) {
       const temp = { shipping_method: method }
@@ -95,12 +94,12 @@ class FulfillmentService extends BaseService {
   async getFulfillmentItems_(order, items, transformer) {
     const toReturn = await Promise.all(
       items.map(async ({ item_id, quantity }) => {
-        const item = order.items.find(i => i.id === item_id)
+        const item = order.items.find((i) => i.id === item_id)
         return transformer(item, quantity)
       })
     )
 
-    return toReturn.filter(i => !!i)
+    return toReturn.filter((i) => !!i)
   }
 
   /**
@@ -137,6 +136,7 @@ class FulfillmentService extends BaseService {
   /**
    * Retrieves a fulfillment by its id.
    * @param {string} id - the id of the fulfillment to retrieve
+   * @param {object} config - optional values to include with fulfillmentRepository query
    * @return {Fulfillment} the fulfillment
    */
   async retrieve(id, config = {}) {
@@ -165,11 +165,11 @@ class FulfillmentService extends BaseService {
    * those partitions.
    * @param {Order} order - order to create fulfillment for
    * @param {{ item_id: string, quantity: number}[]} itemsToFulfill - the items in the order to fulfill
-   * @param {object} metadata - potential metadata to add
+   * @param {object} custom - potential custom values to add
    * @return {Fulfillment[]} the created fulfillments
    */
   async createFulfillment(order, itemsToFulfill, custom = {}) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const fulfillmentRepository = manager.getCustomRepository(
         this.fulfillmentRepository_
       )
@@ -190,18 +190,19 @@ class FulfillmentService extends BaseService {
           const ful = fulfillmentRepository.create({
             ...custom,
             provider_id: shipping_method.shipping_option.provider_id,
-            items: items.map(i => ({ item_id: i.id, quantity: i.quantity })),
+            items: items.map((i) => ({ item_id: i.id, quantity: i.quantity })),
             data: {},
           })
 
-          let result = await fulfillmentRepository.save(ful)
+          const result = await fulfillmentRepository.save(ful)
 
-          result.data = await this.fulfillmentProviderService_.createFulfillment(
-            shipping_method,
-            items,
-            { ...order },
-            { ...result }
-          )
+          result.data =
+            await this.fulfillmentProviderService_.createFulfillment(
+              shipping_method,
+              items,
+              { ...order },
+              { ...result }
+            )
 
           return fulfillmentRepository.save(result)
         })
@@ -220,7 +221,7 @@ class FulfillmentService extends BaseService {
    *
    */
   cancelFulfillment(fulfillmentOrId) {
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       let id = fulfillmentOrId
       if (typeof fulfillmentOrId === "object") {
         id = fulfillmentOrId.id
@@ -260,9 +261,9 @@ class FulfillmentService extends BaseService {
 
   /**
    * Creates a shipment by marking a fulfillment as shipped. Adds
-   * tracking numbers and potentially more metadata.
+   * tracking links and potentially more metadata.
    * @param {Order} fulfillmentId - the fulfillment to ship
-   * @param {TrackingLink[]} trackingNumbers - tracking numbers for the shipment
+   * @param {TrackingLink[]} trackingLinks - tracking links for the shipment
    * @param {object} config - potential configuration settings, such as no_notification and metadata
    * @return {Fulfillment} the shipped fulfillment
    */
@@ -276,7 +277,7 @@ class FulfillmentService extends BaseService {
   ) {
     const { metadata, no_notification } = config
 
-    return this.atomicPhase_(async manager => {
+    return this.atomicPhase_(async (manager) => {
       const fulfillmentRepository = manager.getCustomRepository(
         this.fulfillmentRepository_
       )
@@ -298,7 +299,7 @@ class FulfillmentService extends BaseService {
       const now = new Date()
       fulfillment.shipped_at = now
 
-      fulfillment.tracking_links = trackingLinks.map(tl =>
+      fulfillment.tracking_links = trackingLinks.map((tl) =>
         trackingLinkRepo.create(tl)
       )