Add type information here and there

.eslintrc.js

@@ -265,11 +265,11 @@ module.exports = {
         '@typescript-eslint/no-empty-interface': 0,
         '@typescript-eslint/no-unused-vars': 0,
         '@typescript-eslint/triple-slash-reference': 0,
-        '@typescript-eslint/ban-ts-ignore': 0,
+        '@typescript-eslint/ban-ts-comment': 'off',
         '@typescript-eslint/no-empty-function': 0,
         '@typescript-eslint/camelcase': 0,
         '@typescript-eslint/no-explicit-any': 0,
-        '@typescript-eslint/explicit-function-return-type': 0,
+        '@typescript-eslint/explicit-function-return-type': 'error',
         '@typescript-eslint/no-var-requires': 0,
         'prefer-rest-params': 'off',
       },

src/Error.ts

@@ -1,35 +1,4 @@
 /* eslint-disable camelcase */
-type RawErrorType =
-  | 'card_error'
-  | 'invalid_request_error'
-  | 'api_error'
-  | 'idempotency_error'
-  | 'rate_limit_error'
-  | 'authentication_error'
-  | 'invalid_grant';
-
-type StripeRawError = {
-  message?: string;
-  type?: RawErrorType;
-
-  headers?: {[header: string]: string};
-  statusCode?: number;
-  requestId?: string;
-  code?: string;
-  doc_url?: string;
-  decline_code?: string;
-  param?: string;
-  detail?: string;
-  charge?: string;
-  payment_method_type?: string;
-
-  payment_intent?: any;
-  payment_method?: any;
-  setup_intent?: any;
-  source?: any;
-  exception?: any;
-};
-
 /**
  * StripeError is the base error from which all other more specific Stripe errors derive.
  * Specifically for errors returned from Stripe's REST API.
@@ -38,9 +7,9 @@ class StripeError extends Error {
   readonly message: string;
   readonly type: string;
   readonly raw: unknown;
-  readonly rawType: RawErrorType;
-  readonly headers: {[header: string]: string};
-  readonly requestId: string;
+  readonly rawType?: RawErrorType;
+  readonly headers?: {[header: string]: string};
+  readonly requestId?: string;
 
   readonly code?: string;
   readonly doc_url?: string;
@@ -69,6 +38,7 @@ class StripeError extends Error {
     this.headers = raw.headers;
     this.requestId = raw.requestId;
     this.statusCode = raw.statusCode;
+    // @ts-ignore
     this.message = raw.message;
 
     this.charge = raw.charge;
@@ -83,7 +53,7 @@ class StripeError extends Error {
   /**
    * Helper factory which takes raw stripe errors and outputs wrapping instances
    */
-  static generate(rawStripeError) {
+  static generate(rawStripeError: StripeRawError): StripeError {
     switch (rawStripeError.type) {
       case 'card_error':
         return new StripeCardError(rawStripeError);

src/ResourceNamespace.ts

@@ -1,19 +1,26 @@
 // ResourceNamespace allows you to create nested resources, i.e. `stripe.issuing.cards`.
 // It also works recursively, so you could do i.e. `stripe.billing.invoicing.pay`.
 
-function ResourceNamespace(stripe, resources) {
+function ResourceNamespace(
+  this: StripeResourceNamespaceObject,
+  stripe: StripeObject,
+  resources: Array<StripeResourceObject>
+): void {
   for (const name in resources) {
     const camelCaseName = name[0].toLowerCase() + name.substring(1);
 
-    const resource = new resources[name](stripe);
+    const resource = new (resources[name] as any)(stripe);
 
     this[camelCaseName] = resource;
   }
 }
 
-module.exports = function(namespace, resources) {
-  return function(stripe) {
-    return new ResourceNamespace(stripe, resources);
+module.exports = function(
+  namespace: string,
+  resources: Array<StripeResourceObject>
+): (stripe: StripeObject) => StripeResourceNamespaceObject {
+  return function(stripe: StripeObject): StripeResourceNamespaceObject {
+    return new (ResourceNamespace as any)(stripe, resources);
   };
 };
 

src/StripeMethod.ts

@@ -19,13 +19,13 @@ const makeAutoPaginationMethods = autoPagination.makeAutoPaginationMethods;
  *  Usefully for applying transforms to data on a per-method basis.
  * @param [spec.host] Hostname for the request.
  */
-function stripeMethod(spec) {
+function stripeMethod(spec: MethodSpec): (...args: any[]) => Promise<any> {
   if (spec.path !== undefined && spec.fullPath !== undefined) {
     throw new Error(
       `Method spec specified both a 'path' (${spec.path}) and a 'fullPath' (${spec.fullPath}).`
     );
   }
-  return function(...args) {
+  return function(this: StripeResourceObject, ...args: any[]): Promise<any> {
     const callback = typeof args[args.length - 1] == 'function' && args.pop();
 
     spec.urlParams = utils.extractUrlParams(