diff --git a/lib/__tests__/manifest-values.spec.ts b/lib/__tests__/manifest-values.spec.ts
index 677c401..e53b76e 100644
--- a/lib/__tests__/manifest-values.spec.ts
+++ b/lib/__tests__/manifest-values.spec.ts
@@ -52,11 +52,11 @@ describe('scrypto value', () => {
     [Enum('Foo'), 'Enum("Foo")'],
     [
       Enum('Foo', String('some string'), Bool(false)),
-      'Enum("Foo","some string",false)',
+      'Enum("Foo", "some string", false)',
     ],
-    [Enum('Some', String('foobar')), 'Enum("Some","foobar")'],
-    [Enum('Some', U128('128')), 'Enum("Some",128u128)'],
-    [Enum('Some', Decimal(219.01234)), 'Enum("Some",Decimal("219.01234"))'],
+    [Enum('Some', String('foobar')), 'Enum("Some", "foobar")'],
+    [Enum('Some', U128('128')), 'Enum("Some", 128u128)'],
+    [Enum('Some', Decimal(219.01234)), 'Enum("Some", Decimal("219.01234"))'],
     [Enum('None'), 'Enum("None")'],
     [Tuple(Decimal(42.42), String('foo')), 'Tuple(Decimal("42.42"),"foo")'],
     [Tuple(Decimal(42.42), String('foo')), 'Tuple(Decimal("42.42"),"foo")'],
@@ -214,8 +214,8 @@ describe('manifest builder', () => {
           Address(
             'component_sim1q0kryz5scup945usk39qjc2yjh6l5zsyuh8t7v5pk0tshjs68x'
           ),
-          'key',
-          Enum(0, Enum(0, 'value')),
+          String('key'),
+          Enum(0, Enum(0, String('value'))),
         ])
         .build()
         .toString()
diff --git a/lib/manifest-builder.ts b/lib/manifest-builder.ts
index 270dfc5..4454113 100644
--- a/lib/manifest-builder.ts
+++ b/lib/manifest-builder.ts
@@ -85,9 +85,9 @@ export class ManifestBuilder {
     resourceAddress: AddressString,
     bucketName: string
   ): ManifestBuilder {
-    var temp = nonFungibleLocalIds
+    let temp = nonFungibleLocalIds
       .map(function (id) {
-        'NonFungibleLocalId("' + id + '")'
+        return 'NonFungibleLocalId("' + id + '")'
       })
       .join(', ')
     this.instructions.push(
@@ -153,9 +153,9 @@ export class ManifestBuilder {
     nonFungibleLocalIds: NonFungibleLocalIdString[],
     resourceAddress: AddressString
   ): ManifestBuilder {
-    var temp = nonFungibleLocalIds
+    let temp = nonFungibleLocalIds
       .map(function (id) {
-        'NonFungibleLocalId("' + id + '")'
+        return 'NonFungibleLocalId("' + id + '")'
       })
       .join(', ')
     this.instructions.push(
@@ -254,9 +254,9 @@ export class ManifestBuilder {
     resourceAddress: AddressString,
     proofName: string
   ): ManifestBuilder {
-    var temp = nonFungibleLocalIds
+    let temp = nonFungibleLocalIds
       .map(function (id) {
-        'NonFungibleLocalId("' + id + '")'
+        return 'NonFungibleLocalId("' + id + '")'
       })
       .join(', ')
     this.instructions.push(
@@ -388,7 +388,7 @@ export class ManifestBuilder {
     this.instructions.push(
       `CALL_METHOD ${Address(accountAddress)} "withdraw" ${Address(
         resourceAddress
-      )} ${Decimal(amount)} ;`
+      )} ${Decimal(amount)};`
     )
     return this
   }
@@ -406,9 +406,9 @@ export class ManifestBuilder {
     resourceAddress: AddressString,
     nonFungibleLocalIds: NonFungibleLocalIdString[]
   ): ManifestBuilder {
-    var temp = nonFungibleLocalIds
+    let temp = nonFungibleLocalIds
       .map(function (id) {
-        'NonFungibleLocalId("' + id + '")'
+        return 'NonFungibleLocalId("' + id + '")'
       })
       .join(', ')
     this.instructions.push(
@@ -416,7 +416,7 @@ export class ManifestBuilder {
         accountAddress
       )} "withdraw_non_fungibles" ${Address(
         resourceAddress
-      )} Array<NonFungibleLocalId>(${temp})};`
+      )} Array<NonFungibleLocalId>(${temp});`
     )
     return this
   }
@@ -476,9 +476,9 @@ export class ManifestBuilder {
     resourceAddress: AddressString,
     nonFungibleLocalIds: NonFungibleLocalIdString[]
   ): ManifestBuilder {
-    var temp = nonFungibleLocalIds
+    let temp = nonFungibleLocalIds
       .map(function (id) {
-        'NonFungibleLocalId("' + id + '")'
+        return 'NonFungibleLocalId("' + id + '")'
       })
       .join(', ')
     this.instructions.push(
diff --git a/lib/manifest-value.ts b/lib/manifest-value.ts
index b4149a6..50d8fc6 100644
--- a/lib/manifest-value.ts
+++ b/lib/manifest-value.ts
@@ -138,11 +138,11 @@ export const String = <T extends string>(str: T): `"${T}"` => {
 export const Enum = (field: string | number, ...args: string[]): string => {
   if (typeof field === 'number') {
     return args.length > 0
-      ? `Enum(${field}u8,${args.join(',')})`
+      ? `Enum(${field}u8, ${args.join(', ')})`
       : `Enum(${field}u8)`
   } else {
     return args.length > 0
-      ? `Enum("${field}",${args.join(',')})`
+      ? `Enum("${field}", ${args.join(', ')})`
       : `Enum("${field}")`
   }
 }