chore: use literal union type instead of enums

In order to be able to generate two versions of the codegen:
- one for the backend generated from the "admin" permissions
- one for the frontend generated from the "org_owner" permissions

we need to replace enums by literals unions so that we can share some code between the 2 SDKs. Indeed, when using enums, Typescript complains about not having any overlap between enums even if they have the same values:
<img width="988" alt="image" src="https://user-images.githubusercontent.com/2678610/161303594-c9030409-a855-487e-94a8-dd6448a7a2c9.png"> ([code](https://www.typescriptlang.org/play?#code/KYDwDg9gTgLgBMAdgVwLYJag+gZwJapgA2wcA3gLABQccAxgIY7ACMcAvHAOSPMtcAaarV7AATB26ixg6gF9qoSLAxpV2fIRJYJlGvSatJPQ-yH7px6bKoKq1OhEQ4IJAHREIAcwAUSNLgExMBuomzsEeqBWsA6AJRAA))

While string literals unions can simply be compared:
<img width="290" alt="image" src="https://user-images.githubusercontent.com/2678610/161303751-b0d9bc5f-7b7b-46db-b926-553a9faba1ad.png">

Another benefit of using string literals unions is that they are non generated to the build output.

Author: ValentinH

src/TreeToTS/templates/modelTypes/index.ts

@@ -1,6 +1,7 @@
 import { plusDescription } from '@/TreeToTS/templates/shared/description';
 import { resolveField } from '@/TreeToTS/templates/shared/field';
 import { ParserField, TypeSystemDefinition, TypeDefinition } from 'graphql-js-tree';
+import { toTypeNameFromEnum } from '../shared/enums';
 
 export const MODEL_TYPES = 'ModelTypes';
 
@@ -9,7 +10,7 @@ const resolveTypeFromRoot = (i: ParserField, rootNodes: ParserField[]): string =
     return '';
   }
   if (i.data.type === TypeDefinition.EnumTypeDefinition) {
-    return `["${i.name}"]:${i.name}`;
+    return `["${i.name}"]:${toTypeNameFromEnum(i.name)}`;
   }
   if (i.data.type === TypeDefinition.ScalarTypeDefinition) {
     return `${plusDescription(i.description)}["${i.name}"]:any`;

src/TreeToTS/templates/returnedTypes/enum.ts

@@ -1,11 +1,12 @@
 import { plusDescription } from '@/TreeToTS/templates/shared/description';
 import { ParserField } from 'graphql-js-tree';
+import { toTypeNameFromEnum } from '../shared/enums';
 
 export const resolveEnum = (i: ParserField): string => {
   if (!i.args) {
     throw new Error('Empty enum error');
   }
-  return `${plusDescription(i.description)}export const enum ${i.name} {\n${i.args
-    .map((f) => `\t${f.name} = "${f.name}"`)
-    .join(',\n')}\n}`;
+  const typeName = toTypeNameFromEnum(i.name);
+  const stringLiterals = i.args.map((f) => `'${f.name}'`).join(' | ');
+  return `${plusDescription(i.description)}export type ${typeName} = ${stringLiterals}\n`;
 };

src/TreeToTS/templates/returnedTypes/index.ts

@@ -4,11 +4,12 @@ import { resolveUnionMember } from '@/TreeToTS/templates/returnedTypes/unionMemb
 import { plusDescription } from '@/TreeToTS/templates/shared/description';
 import { resolveField } from '@/TreeToTS/templates/shared/field';
 import { ParserField, TypeDefinition, TypeSystemDefinition, Helpers } from 'graphql-js-tree';
+import { toTypeNameFromEnum } from '../shared/enums';
 
 const resolveType = ({ data, name, args }: ParserField, rootNodes: ParserField[]) => {
   switch (data.type) {
     case TypeDefinition.EnumTypeDefinition:
-      return `["${name}"]: ${name}`;
+      return `["${name}"]: ${toTypeNameFromEnum(name)}`;
     case TypeDefinition.InputObjectTypeDefinition:
       return `["${name}"]: {\n\t${args.map((f) => resolveField(f)).join(',\n')}\n}`;
 

src/TreeToTS/templates/shared/enums.ts

@@ -0,0 +1,6 @@
+export const toTypeNameFromEnum = (enumName: string) => {
+  return enumName
+    .split('_')
+    .map((part) => `${part[0].toUpperCase()}${part.slice(1).toLowerCase()}`)
+    .join('');
+};

src/TreeToTS/templates/valueTypes/index.ts

@@ -3,6 +3,7 @@ import { ParserField, TypeSystemDefinition, Helpers, TypeDefinition, getTypeName
 import { createValueType, resolveArg, resolveValueField } from '@/TreeToTS/templates/valueTypes/arg';
 import { plusDescription } from '@/TreeToTS/templates/shared/description';
 import { VALUETYPES } from '@/TreeToTS/templates/valueTypes/models';
+import { toTypeNameFromEnum } from '../shared/enums';
 
 const AliasType = (code: string): string => `AliasType<${code}>`;
 const resolveValueTypeFromRoot = (i: ParserField, rootNodes: ParserField[], enumsAndScalars: string[]): string => {
@@ -19,7 +20,7 @@ const resolveValueTypeFromRoot = (i: ParserField, rootNodes: ParserField[], enum
     )}`;
   }
   if (i.data.type === TypeDefinition.EnumTypeDefinition) {
-    return `["${i.name}"]:${i.name}`;
+    return `["${i.name}"]:${toTypeNameFromEnum(i.name)}`;
   }
   if (i.data.type === TypeDefinition.InputObjectTypeDefinition) {
     return `["${i.name}"]: {\n${i.args.map((f) => resolveArg(f)).join(',\n')}\n}`;

src/TreeToTS/templates/valueTypes/inputTypes/index.ts

@@ -3,14 +3,15 @@ import { ParserField, TypeSystemDefinition, Helpers, TypeDefinition } from 'grap
 import { createInputType, resolveInputArg, resolveInputField } from '@/TreeToTS/templates/valueTypes/inputTypes/arg';
 import { plusDescription } from '@/TreeToTS/templates/shared/description';
 import { INPUTTYPES } from '@/TreeToTS/templates/valueTypes/models';
+import { toTypeNameFromEnum } from '../../shared/enums';
 
 const AliasType = (code: string): string => `AliasType<${code}>`;
 const resolveValueTypeFromRoot = (i: ParserField, rootNodes: ParserField[], enumsAndScalars: string[]): string => {
   if (!i.args || !i.args.length) {
     return `["${i.name}"]:unknown`;
   }
   if (i.data.type === TypeDefinition.EnumTypeDefinition) {
-    return `["${i.name}"]:${i.name}`;
+    return `["${i.name}"]:${toTypeNameFromEnum(i.name)}`;
   }
   if (i.data.type === TypeDefinition.InputObjectTypeDefinition) {
     return `["${i.name}"]: {\n${i.args.map((f) => resolveInputArg(f)).join(',\n')}\n}`;