Build link helper (#69)

* initial buildLink helper
 🐿 v2.9.0

* add unit tests
 🐿 v2.9.0

* bump circle testing to node 8
 🐿 v2.9.0

* add default param
 🐿 v2.9.0

circle.yml

@@ -1,6 +1,6 @@
 machine:
   node:
-    version: 6.11.0
+    version: 8.11.3
 
 deployment:
   release:

package.json

@@ -19,7 +19,7 @@
     "handlebars": "^4.0.0"
   },
   "devDependencies": {
-    "@financial-times/n-gage": "^1.19.4",
+    "@financial-times/n-gage": "^1.19.14",
     "chai": "^3.3.0",
     "eslint": "^3.2.2",
     "express": "^4.12.3",

src/extend-helpers.js

@@ -27,6 +27,7 @@ module.exports = function (helpers) {
 	helpers.debug = require('./helpers/debug');
 	helpers.array = require('./helpers/array');
 	helpers.inline = require('./helpers/inline');
+	helpers.buildLink = require('./helpers/buildLink');
 	helpers.nImagePresenter = require('@financial-times/n-image/src/handlebars-helpers/nImagePresenter');
 	helpers.concept = require('@financial-times/n-topic-card/handlebars-helpers/concept');
 

src/helpers/buildLink.js

@@ -0,0 +1,10 @@
+const { URL } = require('url');
+
+module.exports = function (url, queryParams = {}) {
+	if (!url) return '';
+	const urlObject = new URL(url);
+	Object.keys(queryParams).forEach(key => {
+		urlObject.searchParams.set(key, queryParams[key]);
+	});
+	return urlObject.href;
+};

test/buildLink.spec.js

@@ -0,0 +1,28 @@
+const { expect } = require('chai');
+const buildLink = require('../src/helpers/buildLink');
+
+describe('Build Link Helper', () => {
+
+	const url = 'https://ft.com/somePath';
+	const queryParams = {
+		cpccampaign: 'test',
+		something: 'else'
+	};
+
+	it('should correctly generate links', () => {
+		expect(buildLink(url, queryParams)).to.equal('https://ft.com/somePath?cpccampaign=test&something=else');
+	});
+
+	it('should return an empty string if no URL specified', () => {
+		expect(buildLink()).to.equal('');
+	});
+
+	it('should not break if no query params are passed', () => {
+		expect(buildLink(url)).to.equal(url);
+	});
+
+	it('should not duplicate query params', () => {
+		const urlWithParam = `${url}?something=new`;
+		expect(buildLink(urlWithParam, queryParams)).to.equal('https://ft.com/somePath?something=else&cpccampaign=test');
+	});
+});