Add flatten option for non-anonymous structs (#47)

Author: mike-hosseini

json-to-go.js

@@ -7,12 +7,17 @@
 	A simple utility to translate JSON into a Go type definition.
 */
 
-function jsonToGo(json, typename)
+function jsonToGo(json, typename, flatten = true)
 {
-	var data;
-	var scope;
-	var go = "";
-	var tabs = 0;
+	let data;
+	let scope;
+	let go = "";
+	let tabs = 0;
+
+	let accumulator = "";
+	let innerTabs = 0;
+	let stack = [];
+	let parent = "";
 
 	try
 	{
@@ -28,25 +33,29 @@ function jsonToGo(json, typename)
 	}
 
 	typename = format(typename || "AutoGenerated");
-	append("type "+typename+" ");
+	append(`type ${typename} `);
 
 	parseScope(scope);
-	
-	return { go: go };
 
+	return {
+		go: flatten
+			? go += accumulator
+			: go
+	};
 
 
-	function parseScope(scope)
+	function parseScope(scope, depth = 0)
 	{
 		if (typeof scope === "object" && scope !== null)
 		{
 			if (Array.isArray(scope))
 			{
-				var sliceType, scopeLength = scope.length;
+				let sliceType;
+				const scopeLength = scope.length;
 
-				for (var i = 0; i < scopeLength; i++)
+				for (let i = 0; i < scopeLength; i++)
 				{
-					var thisType = goType(scope[i]);
+					const thisType = goType(scope[i]);
 					if (!sliceType)
 						sliceType = thisType;
 					else if (sliceType != thisType)
@@ -57,17 +66,20 @@ function jsonToGo(json, typename)
 					}
 				}
 
-				append("[]");
+				if (flatten && depth >= 2)
+					appender("[]");
+				else
+					append("[]")
 				if (sliceType == "struct") {
-					var allFields = {};
+					const allFields = {};
 
 					// for each field counts how many times appears
-					for (var i = 0; i < scopeLength; i++)
+					for (let i = 0; i < scopeLength; i++)
 					{
-						var keys = Object.keys(scope[i])
-						for (var k in keys)
+						const keys = Object.keys(scope[i])
+						for (let k in keys)
 						{
-							var keyname = keys[k];
+							const keyname = keys[k];
 							if (!(keyname in allFields)) {
 								allFields[keyname] = {
 									value: scope[i][keyname],
@@ -78,61 +90,117 @@ function jsonToGo(json, typename)
 							allFields[keyname].count++;
 						}
 					}
-					
+
 					// create a common struct with all fields found in the current array
 					// omitempty dict indicates if a field is optional
-					var keys = Object.keys(allFields), struct = {}, omitempty = {};
-					for (var k in keys)
+					const keys = Object.keys(allFields), struct = {}, omitempty = {};
+					for (let k in keys)
 					{
-						var keyname = keys[k], elem = allFields[keyname];
+						const keyname = keys[k], elem = allFields[keyname];
 
 						struct[keyname] = elem.value;
 						omitempty[keyname] = elem.count != scopeLength;
 					}
-
-					parseStruct(struct, omitempty); // finally parse the struct !!
+					parseStruct(depth + 1, innerTabs, struct, omitempty); // finally parse the struct !!
 				}
 				else if (sliceType == "slice") {
-					parseScope(scope[0])
+					parseScope(scope[0], depth)
+				}
+				else {
+					if (flatten && depth >= 2) {
+						appender(sliceType || "interface{}");
+					} else {
+						append(sliceType || "interface{}");
+					}
 				}
-				else
-					append(sliceType || "interface{}");
 			}
 			else
 			{
-				parseStruct(scope);
+				if (flatten) {
+					if (depth >= 2){
+						appender(parent)
+					}
+					else {
+						append(parent)
+					}
+				}
+				parseStruct(depth + 1, innerTabs, scope);
+			}
+		}
+		else {
+			if (depth >= 2){
+				appender(goType(scope));
+			}
+			else {
+				append(goType(scope));
 			}
 		}
-		else
-			append(goType(scope));
 	}
 
-	function parseStruct(scope, omitempty)
+	function parseStruct(depth, innerTabs, scope, omitempty)
 	{
-		append("struct {\n");
-		++tabs;
-		var keys = Object.keys(scope);
-		for (var i in keys)
-		{
-			var keyname = keys[i];
-			indent(tabs);
-			append(format(keyname)+" ");
-			parseScope(scope[keyname]);
+		if (flatten) {
+			stack.push(
+				depth >= 2
+				? "\n"
+				: ""
+			)
+		}
 
-			append(' `json:"'+keyname);
-			if (omitempty && omitempty[keyname] === true)
+		if (flatten && depth >= 2)
+		{
+			appender(`type ${parent} ` + "struct {\n");
+			++innerTabs;
+			const keys = Object.keys(scope);
+			for (let i in keys)
 			{
-				append(',omitempty');
+				const keyname = keys[i];
+				indenter(innerTabs)
+				const typename = format(keyname)
+				appender(typename+" ");
+				parent = typename
+				parseScope(scope[keyname], depth);
+				appender(' `json:"'+keyname);
+				if (omitempty && omitempty[keyname] === true)
+				{
+					appender(',omitempty');
+				}
+				appender('"`\n');
+			}
+			indenter(--innerTabs);
+			appender("}");
+		}
+		else
+		{
+			append("struct {\n");
+			++tabs;
+			const keys = Object.keys(scope);
+			for (let i in keys)
+			{
+				const keyname = keys[i];
+				indent(tabs);
+				const typename = format(keyname);
+				append(typename+" ");
+				parent = typename
+				parseScope(scope[keyname], depth);
+
+				append(' `json:"'+keyname);
+				if (omitempty && omitempty[keyname] === true)
+				{
+					append(',omitempty');
+				}
+				append('"`\n');
 			}
-			append('"`\n');
+			indent(--tabs);
+			append("}");
 		}
-		indent(--tabs);
-		append("}");
+		if (flatten)
+			accumulator += stack.pop();
 	}
 
 	function indent(tabs)
 	{
-		for (var i = 0; i < tabs; i++)
+		for (let i = 0; i < tabs; i++)
 			go += '\t';
 	}
 
@@ -141,6 +209,17 @@ function jsonToGo(json, typename)
 		go += str;
 	}
 
+	function indenter(tabs)
+	{
+		for (let i = 0; i < tabs; i++)
+			stack[stack.length - 1] += '\t';
+	}
+
+	function appender(str)
+	{
+		stack[stack.length - 1] += str;
+	}
+
 	// Sanitizes and formats a string to make an appropriate identifier in Go
 	function format(str)
 	{
@@ -150,7 +229,7 @@ function jsonToGo(json, typename)
 			str = "Num" + str;
 		else if (str.charAt(0).match(/\d/))
 		{
-			var numbers = {'0': "Zero_", '1': "One_", '2': "Two_", '3': "Three_",
+			const numbers = {'0': "Zero_", '1': "One_", '2': "Two_", '3': "Three_",
 				'4': "Four_", '5': "Five_", '6': "Six_", '7': "Seven_",
 				'8': "Eight_", '9': "Nine_"};
 			str = numbers[str.charAt(0)] + str.substr(1);
@@ -163,7 +242,7 @@ function jsonToGo(json, typename)
 	{
 		if (val === null)
 			return "interface{}";
-		
+
 		switch (typeof val)
 		{
 			case "string":
@@ -209,10 +288,10 @@ function jsonToGo(json, typename)
 	function toProperCase(str)
 	{
 		// https://github.com/golang/lint/blob/39d15d55e9777df34cdffde4f406ab27fd2e60c0/lint.go#L695-L731
-		var commonInitialisms = [
-			"API", "ASCII", "CPU", "CSS", "DNS", "EOF", "GUID", "HTML", "HTTP", 
-			"HTTPS", "ID", "IP", "JSON", "LHS", "QPS", "RAM", "RHS", "RPC", "SLA", 
-			"SMTP", "SSH", "TCP", "TLS", "TTL", "UDP", "UI", "UID", "UUID", "URI", 
+		const commonInitialisms = [
+			"API", "ASCII", "CPU", "CSS", "DNS", "EOF", "GUID", "HTML", "HTTP",
+			"HTTPS", "ID", "IP", "JSON", "LHS", "QPS", "RAM", "RHS", "RPC", "SLA",
+			"SMTP", "SSH", "TCP", "TLS", "TTL", "UDP", "UI", "UID", "UUID", "URI",
 			"URL", "UTF8", "VM", "XML", "XSRF", "XSS"
 		];
 
@@ -235,10 +314,10 @@ function jsonToGo(json, typename)
 if (typeof module != 'undefined') {
     if (!module.parent) {
         process.stdin.on('data', function(buf) {
-            var json = buf.toString('utf8')
+            const json = buf.toString('utf8')
             console.log(jsonToGo(json).go)
         })
     } else {
         module.exports = jsonToGo
     }
-}
+}