Add date helper lib

...to support the next commit, which will use this lib in all flight booker implementations

lib/Readme.md

@@ -0,0 +1,3 @@
+# Lib
+
+This folder contains code shared across apps implemented by all the frameworks

lib/date.js

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+export function today() {
+	const fullDate = new Date();
+	let month = fullDate.getMonth() + 1;
+	let date = fullDate.getDate();
+	return [
+		fullDate.getFullYear(),
+		month < 10 ? "0" + month : month,
+		date < 10 ? "0" + date : date
+	].join("-");
+}
+
+const validDate = /^([0-9]{4})-([0-9]{1,2})-([0-9]{1,2})$/;
+
+/**
+ * @param {string} date
+ */
+export function validateDate(date) {
+	if (date == null) {
+		throw new Error("Invalid date. Date must be in the format of YYYY-MM-DD");
+	}
+
+	const match = date.match(validDate);
+	if (match == null) {
+		throw new Error("Invalid date. Date must be in the format of YYYY-MM-DD");
+	}
+
+	const year = parseInt(match[1]);
+	const month = parseInt(match[2]);
+	const day = parseInt(match[3]);
+
+	if (day < 1 || day > 31) {
+		throw new Error("Invalid date. Date must be between 1-31.");
+	}
+
+	if (month < 1 || month > 12) {
+		throw new Error("Invalid month. Month must be between 1-12.");
+	}
+
+	const parsedDate = new Date(date);
+
+	if (day !== parsedDate.getUTCDate()) {
+		throw new Error("Invalid date. Date isn't correct.");
+	}
+
+	if (month !== parsedDate.getUTCMonth() + 1) {
+		throw new Error("Invalid date. Month isn't correct.");
+	}
+
+	if (year !== parsedDate.getUTCFullYear()) {
+		throw new Error("Invalid date. Year isn't correct.");
+	}
+}

package.json

@@ -36,6 +36,9 @@
     "rollup-plugin-visualizer": "^2.4.4"
   },
   "jest": {
-    "preset": "jest-puppeteer"
+    "preset": "jest-puppeteer",
+    "transform": {
+      "^.+\\.[t|j]sx?$": "<rootDir>/tests/babelTransformer.js"
+    }
   }
 }

tests/babelTransformer.js

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+const babelJest = require("babel-jest");
+
+// By default, babel-jest looks for a babel.config.js to determine the configuration
+// to use to run tests. We don't want to add a babel.config.js at the root of this project
+// because not all subpackages (e.g. Svelte, Vue) use Babel and we wouldn't want the presence
+// of this global babel config to mess with the building of these packages. However, we do
+// want all of our test files to be run through Babel so instead of messing around with config
+// files which didn't intuitively work (specifically the date.test.js file cuz it imports a file
+// outside of the "tests" directory where we could put a babel config), we are manually specifying
+// a Babel config here
+module.exports = babelJest.createTransformer({
+	presets: [
+		[
+			"@babel/preset-env",
+			{
+				targets: {
+					node: "current"
+				}
+			}
+		],
+		[
+			"@babel/preset-react",
+			{
+				pragma: "toHtmlString",
+				pragmaFrag: "toHtmlString.Fragment"
+			}
+		]
+	]
+});

tests/lib/date.test.js

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+import { validateDate, today } from "../../lib/date";
+
+describe("date lib", () => {
+	describe("today()", () => {
+		it("returns a valid date", () => {
+			expect(() => validateDate(today())).not.toThrow();
+		});
+	});
+
+	describe("validateDate", () => {
+		it("does not throw errors on valid date formats", () => {
+			expect(() => validateDate("2018-09-12")).not.toThrowError();
+			expect(() => validateDate("2019-1-12")).not.toThrowError();
+			expect(() => validateDate("2018-09-2")).not.toThrowError();
+			expect(() => validateDate("2019-1-2")).not.toThrowError();
+			expect(() => validateDate("2019-02-28")).not.toThrowError();
+			expect(() => validateDate("2024-02-29")).not.toThrowError();
+		});
+
+		it("throws helpful errors on invalid date formats", () => {
+			expect(() => validateDate(null)).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("-")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("--")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("---")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1234--")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1234-09-")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("-09-")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("-09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1234--01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("123-09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("12-09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1-09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("12345-09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("a1234-09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1a234-09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("12a34-09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("123a4-09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1234a-09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1234-a09-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1234-0a9-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1234-09a-01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1234-09-a01")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1234-09-0a1")).toThrowError(/YYYY-MM-DD/);
+			expect(() => validateDate("1234-09-01a")).toThrowError(/YYYY-MM-DD/);
+		});
+
+		it("throws helpful errors on invalid dates", () => {
+			expect(() => validateDate("2019-12-32")).toThrowError(/Date/);
+			expect(() => validateDate("2019-4-31")).toThrowError(/Date/);
+			expect(() => validateDate("2019-02-29")).toThrowError(/Date/);
+			expect(() => validateDate("2019-13-01")).toThrowError(/Month/);
+		});
+	})
+});