From 2f7f701057539c18364d44174d09ce58f9f65450 Mon Sep 17 00:00:00 2001
From: arunkumar <nanaarunae.ak@gmail.com>
Date: Wed, 24 Feb 2021 01:25:36 +0530
Subject: [PATCH] AST to Markdown function and its test cases added

---
 lib/compileASTtoMarkdown.js  | 22 ++++++++++++++
 lib/index.js                 |  3 +-
 test/AST_To_Markdown.test.js | 72 ++++++++++++++++++++++++++++++++++++++++++++
 test/index.test.js           |  7 +----
 4 files changed, 96 insertions(+), 8 deletions(-)
 create mode 100644 lib/compileASTtoMarkdown.js
 create mode 100644 test/AST_To_Markdown.test.js

diff --git a/lib/compileASTtoMarkdown.js b/lib/compileASTtoMarkdown.js
new file mode 100644
index 0000000..d1e7c50
--- /dev/null
+++ b/lib/compileASTtoMarkdown.js
@@ -0,0 +1,22 @@
+const { inspect } = require("util");
+const nodeTypes = {
+	bold: "**",
+	italics: "_",
+	strikethrough: "~~",
+	underline: "==",
+	text: "",
+};
+
+const CompileASTtoMarkdown = ast =>
+	ast.reduce((acc, value) => {
+		if (typeof value === "string") return acc + value;
+		if (value.type === "url") {
+			return acc + `[${CompileASTtoMarkdown(value.children)}](${value.url})`;
+		}
+		let str = nodeTypes[value.type];
+		str += CompileASTtoMarkdown(value.children);
+		str += nodeTypes[value.type];
+		return acc + str;
+	}, "");
+
+module.exports = CompileASTtoMarkdown;
diff --git a/lib/index.js b/lib/index.js
index e109556..f90b1cd 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -13,8 +13,7 @@ function* prepare(str) {
 function Parse(str, inner = false) {
 	let context = null;
 	let buffer = "";
-	let AST = [];
-	let link = "";
+	let AST = [];	let link = "";
 
 	const flush = () => {
 		if (buffer) {
diff --git a/test/AST_To_Markdown.test.js b/test/AST_To_Markdown.test.js
new file mode 100644
index 0000000..114f2e9
--- /dev/null
+++ b/test/AST_To_Markdown.test.js
@@ -0,0 +1,72 @@
+const expect = require("chai").expect;
+const Compile = require("../lib/compileASTtoMarkdown");
+
+describe("Compiling AST to Markdown", function () {
+	it("sample ast - 1", function () {
+		const input = [{ type: "bold", children: ["bold"] }];
+		expect(Compile(input)).to.equal("**bold**");
+	});
+
+	it("sample ast - 2", function () {
+		const input = [
+			{ type: "bold", children: ["my"] },
+			{ type: "text", children: ["simple"] },
+			{ type: "italics", children: ["AST"] },
+		];
+		expect(Compile(input)).to.equal("**my**simple_AST_");
+	});
+
+	it("sentence ast", function () {
+		const input = [
+			{ type: "bold", children: ["Arunkumar"] },
+			{ type: "text", children: [" is the "] },
+			{ type: "underline", children: ["Best Boy"] },
+			{ type: "text", children: [" not the "] },
+			{
+				type: "italics",
+				children: [{ type: "strikethrough", children: ["Worst Boy"] }],
+			},
+			{ type: "text", children: ["."] },
+		];
+		expect(Compile(input)).to.equal(
+			"**Arunkumar** is the ==Best Boy== not the _~~Worst Boy~~_.",
+		);
+	});
+
+	it("link ast", function () {
+		const input = [
+			{ type: "url", children: ["The Feathers"], url: "feathers.studio" },
+		];
+		expect(Compile(input)).to.equal("[The Feathers](feathers.studio)");
+	});
+
+	it("Nested ast", function () {
+		const input = [
+			{
+				type: "bold",
+				children: [
+					"Bold",
+					{
+						type: "italics",
+						children: [
+							"Italics",
+							{
+								type: "strikethrough",
+								children: [
+									"Strikethrough",
+									{ type: "underline", children: ["Underline"] },
+									"Strikethrough",
+								],
+							},
+							"Italics",
+						],
+					},
+					"Bold",
+				],
+			},
+		];
+		expect(Compile(input)).to.equal(
+			"**Bold_Italics~~Strikethrough==Underline==Strikethrough~~Italics_Bold**",
+		);
+	});
+});
diff --git a/test/index.test.js b/test/index.test.js
index 840607e..dfde6f1 100644
--- a/test/index.test.js
+++ b/test/index.test.js
@@ -60,12 +60,7 @@ describe("Parser Checks", function () {
 		expect(
 			Parse(
 				"**Bold_Italics~~strikethrough==underline==strikethrough~~Italics_Bold**",
-			),[
-				{
-				  type: 'underline',
-				  children: [ 'The', { type: 'bold', children: [ 'KING' ] }, 'Maker' ]
-				}
-			  ]
+			),
 		).to.eql([
 			{
 				type: "bold",