feat(Linear Node): Add Linear Node (#2971)

* ✨ Linear node

* ⚡ Improvements

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

@@ -8,13 +8,21 @@ import {
 } from 'n8n-core';
 
 import {
+	ICredentialDataDecryptedObject,
+	ICredentialTestFunctions,
 	IDataObject,
 	IHookFunctions,
 	IWebhookFunctions,
+	JsonObject,
 	NodeApiError,
-	NodeOperationError,
 } from 'n8n-workflow';
 
+import get = require('lodash.get');
+
+import { 
+	query,
+} from './Queries';
+
 export async function linearApiRequest(this: IExecuteFunctions | IWebhookFunctions | IHookFunctions | ILoadOptionsFunctions, body: any = {}, option: IDataObject = {}): Promise<any> { // tslint:disable-line:no-any
 	const credentials = await this.getCredentials('linearApi') as IDataObject;
 
@@ -32,14 +40,60 @@ export async function linearApiRequest(this: IExecuteFunctions | IWebhookFunctio
 	};
 	options = Object.assign({}, options, option);
 	try {
-
 		return await this.helpers.request!(options);
 
 	} catch (error) {
-		throw new NodeApiError(this.getNode(), error);
+		throw new NodeApiError(this.getNode(), error as JsonObject);
 	}
 }
 
 export function capitalizeFirstLetter(data: string) {
 	return data.charAt(0).toUpperCase() + data.slice(1);
-}
+}
+
+export async function linearApiRequestAllItems(this: IHookFunctions | IExecuteFunctions | ILoadOptionsFunctions, propertyName: string, body: any = {}): Promise<any> { // tslint:disable-line:no-any
+
+	const returnData: IDataObject[] = [];
+
+	let responseData;
+	body.variables.first = 50;
+	body.variables.after = null;
+
+	do {
+		responseData = await linearApiRequest.call(this, body);
+		returnData.push.apply(returnData, get(responseData, `${propertyName}.nodes`));
+		body.variables.after = get(responseData, `${propertyName}.pageInfo.endCursor`);
+	} while (
+		get(responseData, `${propertyName}.pageInfo.hasNextPage`)
+	);
+	return returnData;
+}
+
+export async function validateCrendetials(this: ICredentialTestFunctions, decryptedCredentials: ICredentialDataDecryptedObject): Promise<any> { // tslint:disable-line:no-any
+	const credentials = decryptedCredentials;
+
+	const options: OptionsWithUri = {
+		headers: {
+			'Content-Type': 'application/json',
+			Authorization: credentials.apiKey,
+		},
+		method: 'POST',
+		body: {
+			query: query.getIssues(),
+			variables: {
+				first: 1,
+			},
+		},
+		uri: 'https://api.linear.app/graphql',
+		json: true,
+	};
+
+	return this.helpers.request!(options);
+}
+
+//@ts-ignore
+export const sort = (a, b) => {
+	if (a.name.toLocaleLowerCase() < b.name.toLocaleLowerCase()) { return -1; }
+	if (a.name.toLocaleLowerCase() > b.name.toLocaleLowerCase()) { return 1; }
+	return 0;
+};