merge top-level objects inside arrays

Author: grische

json-to-go.js

@@ -52,7 +52,7 @@ function jsonToGo(json, typename, flatten = true, example = false, allOmitempty
 	};
 
 
-	function parseScope(scope, depth = 0)
+	function parseScope(scope, depth = 0, forceOmitEmptyNonArrays = false)
 	{
 		if (typeof scope === "object" && scope !== null)
 		{
@@ -82,8 +82,11 @@ function jsonToGo(json, typename, flatten = true, example = false, allOmitempty
 					appender(slice);
 				else
 					append(slice)
+
+				// TODO: structs need a proper recursive solution to make merging generic
 				if (sliceType == "struct") {
 					const allFields = {};
+					let insideOmitEmpty = false;
 
 					// for each field counts how many times appears
 					for (let i = 0; i < scopeLength; i++)
@@ -112,6 +115,47 @@ function jsonToGo(json, typename, flatten = true, example = false, allOmitempty
 								}
 
 								if (areObjects(existingValue, currentValue)) {
+									const currentKeys = Object.keys(currentValue)
+									const existingKeys = Object.keys(existingValue)
+
+									// try to merge two object fields instead of creating separate ones
+									// TODO: find a proper handling of omitempty for nested structs instead of
+									//       fake-forcing omitempty on all nested elements
+									if (existingKeys.length > 0 && currentKeys.length > 0) {
+										if (!allOmitempty) {
+											// check if any of the existingKeys (which are assumed to be mandatory),
+											// is not in the currentKeys
+											for (const key of existingKeys) {
+												if (!Object.keys(currentKeys).includes(key)) {
+													insideOmitEmpty = true // TODO: only set this one key to omitempty
+													break
+												}
+											}
+										}
+
+										var mergedValues = existingValue
+										for (const key of currentKeys) {
+											// check if key has been found previously
+											if (!Object.keys(mergedValues).includes(key)) {
+												mergedValues[key] = currentValue[key]
+												insideOmitEmpty = true // TODO: only set this one key to omitempty
+												continue
+											}
+
+											// check if types between previously found values and the current value
+											if (!areSameType(mergedValues[key], currentValue[key])) {
+												if (mergedValues[key] !== null) {
+													mergedValues[key] = null // force type "any" if types are not identical
+													console.warn(`Warning: nested key "${key}" uses multiple types. Defaulting to type "any".`)
+												}
+											}
+										}
+
+										allFields[keyname].value = mergedValues;
+										allFields[keyname].count++;
+										continue;
+									}
+
 									const comparisonResult = compareObjectKeys(
 										Object.keys(currentValue),
 										Object.keys(existingValue)
@@ -139,7 +183,7 @@ function jsonToGo(json, typename, flatten = true, example = false, allOmitempty
 						struct[keyname] = elem.value;
 						omitempty[keyname] = elem.count != scopeLength;
 					}
-					parseStruct(depth + 1, innerTabs, struct, omitempty, previousParents); // finally parse the struct !!
+					parseStruct(depth + 1, innerTabs, struct, omitempty, previousParents, insideOmitEmpty); // finally parse the struct !!
 				}
 				else if (sliceType == "slice") {
 					parseScope(scope[0], depth)
@@ -162,7 +206,16 @@ function jsonToGo(json, typename, flatten = true, example = false, allOmitempty
 						append(parent)
 					}
 				}
-				parseStruct(depth + 1, innerTabs, scope, false, previousParents);
+
+				const omitempty = {};
+				if (forceOmitEmptyNonArrays) {
+					const allKeys = Object.keys(scope)
+					for (let k in allKeys) {
+						const keyname = allKeys[k];
+						omitempty[keyname] = true;
+					}
+				}
+				parseStruct(depth + 1, innerTabs, scope, omitempty, previousParents);
 			}
 		}
 		else {
@@ -175,7 +228,7 @@ function jsonToGo(json, typename, flatten = true, example = false, allOmitempty
 		}
 	}
 
-	function parseStruct(depth, innerTabs, scope, omitempty, oldParents)
+	function parseStruct(depth, innerTabs, scope, omitempty, oldParents, insideOmitEmpty)
 	{
 		if (flatten) {
 			stack.push(
@@ -221,7 +274,7 @@ function jsonToGo(json, typename, flatten = true, example = false, allOmitempty
 
 				appender(typename+" ");
 				parent = typename
-				parseScope(scope[keys[i]], depth);
+				parseScope(scope[keys[i]], depth, insideOmitEmpty);
 				appender(' `json:"'+keyname);
 				if (allOmitempty || (omitempty && omitempty[keys[i]] === true))
 				{

json-to-go.test.js

@@ -163,6 +163,7 @@ function testFiles() {
     "duplicate-top-level-structs",
     "double-nested-objects",
     "array-with-nonmatching-types",
+    "array-with-mergable-objects",
   ];
 
   for (const testCase of testCases) {

tests/array-with-mergable-objects.go

@@ -0,0 +1,15 @@
+type AutoGenerated struct {
+	Booleanfield bool `json:"booleanfield"`
+	Inconsistentarray []Inconsistentarray `json:"inconsistentarray"`
+	Date string `json:"date"`
+}
+type Features struct {
+	Age int `json:"age,omitempty"`
+	Height any `json:"height,omitempty"`
+	Gender string `json:"gender,omitempty"`
+}
+type Inconsistentarray struct {
+	ID int `json:"id"`
+	Name string `json:"name"`
+	Features Features `json:"features"`
+}

tests/array-with-mergable-objects.json

@@ -0,0 +1,29 @@
+{
+    "booleanfield": true,
+    "inconsistentarray": [
+        {
+            "id": 1,
+            "name": "John Doe",
+            "features": {
+                "age": 49,
+                "height": 175
+            }
+        },
+        {
+            "id": 2,
+            "name": "Jane Doe",
+            "features": {
+                "height": 164
+            }
+        },
+        {
+            "id": 3,
+            "name": "John Doe",
+            "features": {
+                "gender": "male",
+                "height": "unknown"
+            }
+        }
+    ],
+    "date": "2024-07-22"
+}