✨ Add Twist Node (#1231)

* ✨ Twist Node

* ⚡ Small improvements

* 🔨Fix descriptions

* ⚡ Minor improvements to Twist-Node

Co-authored-by: Harshil <ghagrawal17@gmail.com>
Co-authored-by: Jan Oberhauser <jan.oberhauser@gmail.com>

packages/nodes-base/nodes/Twist/GenericFunctions.ts

@@ -0,0 +1,50 @@
+import {
+	OptionsWithUri,
+} from 'request';
+
+import {
+	IExecuteFunctions,
+	ILoadOptionsFunctions,
+} from 'n8n-core';
+
+import {
+	IDataObject,
+} from 'n8n-workflow';
+
+export async function twistApiRequest(this: IExecuteFunctions | ILoadOptionsFunctions, method: string, endpoint: string, body: any = {}, qs: IDataObject = {}, option: IDataObject = {}): Promise<any> { // tslint:disable-line:no-any
+
+	const options: OptionsWithUri = {
+		method,
+		body,
+		qs,
+		uri: `https://api.twist.com/api/v3${endpoint}`,
+		json: true,
+	};
+
+	if (Object.keys(body).length === 0) {
+		delete options.body;
+	}
+
+	if (Object.keys(qs).length === 0) {
+		delete options.qs;
+	}
+
+	Object.assign(options, option);
+
+	try {
+		//@ts-ignore
+		return await this.helpers.requestOAuth2.call(this, 'twistOAuth2Api', options);
+
+	} catch (error) {
+		if (error.response && error.response.body && error.response.body.error_string) {
+
+			const message = error.response.body.error_string;
+
+			// Try to return the error prettier
+			throw new Error(
+				`Twist error response [${error.statusCode}]: ${message}`,
+			);
+		}
+		throw error;
+	}
+}