From 7b62342eb7cdf0529e9de11f99c138d7d7168c30 Mon Sep 17 00:00:00 2001
From: Maximilian Brune <maximilian.brune@9elements.com>
Date: Thu, 4 Aug 2022 19:09:05 +0200
Subject: [PATCH] Add minify implementation for golang

---
 go.mod         |  3 ++
 minify.go      | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++
 minify_test.go | 72 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 167 insertions(+)
 create mode 100644 go.mod
 create mode 100644 minify.go
 create mode 100644 minify_test.go

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..801193d
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module github.com/getify/JSON.minify/tree/go
+
+go 1.18
diff --git a/minify.go b/minify.go
new file mode 100644
index 0000000..eb3f7f5
--- /dev/null
+++ b/minify.go
@@ -0,0 +1,92 @@
+package minify
+
+import (
+	"strings"
+)
+
+func JsonMinify(json string, stripSpace bool) string {
+	var out strings.Builder
+	indexMultilineComment := -1
+	indexInlineComment := -1
+	inJsonStr := false
+	skip := false
+	for i, r := range json {
+		if skip {
+			skip = false
+			continue
+		}
+		switch r {
+		case '/':
+			if !inJsonStr && indexMultilineComment == -1 && indexInlineComment == -1 {
+				// if currently not in a comment or json string, a slash
+				// could be the beginning of a new comment. look ahead and see
+				if len(json) > i+1 {
+					if json[i+1] == '/' {
+						indexInlineComment = i
+						// since we already looked ahead, we don't need
+						// to consider the next character
+						skip = true
+					} else if json[i+1] == '*' {
+						indexMultilineComment = i
+						// since we already looked ahead, we don't need
+						// to consider the next character
+						skip = true
+					}
+				}
+			}
+		case '*':
+			if indexMultilineComment != -1 {
+				// we are currently in a multiline comment. A star sign could mean
+				// the end of our multiline comment. look ahead and see
+				if len(json) > i+1 {
+					if json[i+1] == '/' {
+						indexMultilineComment = -1
+						// since we already looked ahead, we don't need to consider
+						// the next character
+						skip = true
+						// a bit nasty but since we don't want to print the current
+						// character, we need to skip the rest
+						continue
+					}
+				}
+			}
+		case '"':
+			if inJsonStr {
+				inJsonStr = false
+			} else if !inJsonStr && indexMultilineComment == -1 && indexInlineComment == -1 {
+				// if we are currently not in a comment, a quote sign can only mean
+				// we got into a JSON string
+				inJsonStr = true
+			}
+		case '\\':
+			if len(json) > i+1 {
+				if json[i+1] == '"' {
+					// next quote sign is escaped and therefore looses it's meaning
+					// as start/end of JSON string. put into output and skip both
+					out.WriteRune('\\')
+					out.WriteRune('"')
+					skip = true
+					continue
+				} else if json[i+1] == '\\' {
+					// the next escape must loose it's power to escape stuff
+					// because it itself is escaped
+					out.WriteRune('\\')
+					skip = true
+				}
+			}
+		case '\n':
+			indexInlineComment = -1
+		case '\r':
+			indexInlineComment = -1
+		}
+		if indexMultilineComment == -1 && indexInlineComment == -1 {
+			// only consider in output if character is outside of any comment
+			if !stripSpace || inJsonStr || (r != '\n' && r != '\r' && r != '\t' && r != ' ') {
+				// everything considered a whitespace (line feed, carriage return, tab, whitespace)
+				// is only candidate for output if desired
+				out.WriteRune(r)
+			}
+		}
+	}
+	return out.String()
+}
diff --git a/minify_test.go b/minify_test.go
new file mode 100644
index 0000000..145df16
--- /dev/null
+++ b/minify_test.go
@@ -0,0 +1,72 @@
+package minify
+
+import (
+	"bytes"
+	"testing"
+)
+
+type Test struct {
+	Before string;
+	Expected string;
+}
+
+func TestRemoveComments(t *testing.T) {
+	tests := []Test {
+	{
+		Before: `
+			// this is a JSON file with comments
+			{
+				"foo": "bar",	// this is cool
+				"bar": [
+					"baz", "bum", "zam"
+				],
+			/* the rest of this document is just fluff
+			   in case you are interested. */
+				"something": 10,
+				"else": 20
+			}
+
+			/* NOTE: You can easily strip the whitespace and comments
+			   from such a file with the JSON.minify() project hosted
+			   here on github at http://github.com/getify/JSON.minify
+			*/`,
+		Expected: `{"foo":"bar","bar":["baz","bum","zam"],"something":10,"else":20}`,
+	},
+	{
+		Before: `
+
+			{"/*":"*/","//":"",/*"//"*/"/*/"://
+			"//"}
+			`,
+		Expected: `{"/*":"*/","//":"","/*/":"//"}`,
+	},
+	{
+		Before: `
+			/*
+			this is a
+			multi line comment */{
+
+			"foo"
+			:
+				"bar/*"// something
+				,	"b\\\"az":/*
+			something else */"blah"
+
+			}`,
+		Expected: `{"foo":"bar/*","b\\\"az":"blah"}`,
+	},
+	{
+		Before: `
+			{"foo": "ba\\\"r//", "bar\\\\": "b\\\\\\\"a/*z",
+				"baz\\\\\\\\": /* yay */ "fo\\\\\\\\\\\"*/o"
+			}`,
+		Expected: `{"foo":"ba\\\"r//","bar\\\\":"b\\\\\\\"a/*z","baz\\\\\\\\":"fo\\\\\\\\\\\"*/o"}`,
+	}};
+
+	for _, test := range tests {
+		after := JsonMinify(test.Before, true)
+		if !bytes.Equal([]byte(after), []byte(test.Expected)) {
+			t.Fatalf("Not the same:\nreal:    %s\nExpected:%s\n", after, test.Expected)
+		}
+	}
+}