add support for all basic golang number types

json-to-go.js

@@ -349,6 +349,17 @@ function jsonToGo(json, typename, flatten = true, example = false, allOmitempty
 	// Determines the most appropriate Go type
 	function goType(val)
 	{
+		Number.prototype.numberOfDecimals = function () {
+			if(isNaN(this))	return NaN
+			if(!isFinite(this))	return Infinity
+			// example: 1 || 1e-1 || 4.361170766e+20
+			// try to split by "e" and "."
+			let exponentialString = this.toExponential().toString()
+			exponentialString = exponentialString.split("e")[0] || exponentialString
+			exponentialString = exponentialString.split(".")[1] || exponentialString
+			return exponentialString.length || 0;
+		}
+
 		if (val === null)
 			return "any";
 
@@ -360,15 +371,22 @@ function jsonToGo(json, typename, flatten = true, example = false, allOmitempty
 				else
 					return "string";
 			case "number":
-				if (val % 1 === 0)
-				{
-					if (val > -2147483648 && val < 2147483647)
-						return "int";
-					else
-						return "int64";
-				}
-				else
+				// avoid type "int", as its size is platform dependent
+				if (val % 1 === 0 && val >= -128 && val <= 127)
+					return "int8"
+				if (val % 1 === 0 && val >= -32768  && val <= 32767)
+					return "int16"
+				if (val % 1 === 0 && val >= -2147483648 && val <= 2147483647)
+					return "int32"
+				if (val % 1 === 0 && val >= -9223372036854775808 && val <= 9223372036854775807)
+					return "int64"
+				if (val.numberOfDecimals() <= 7 && val > -3.4e+38 && val < 3.4e+38)
+					return "float32"
+				if (val.numberOfDecimals() <= 15 && val > -1.7e+308 && val < +1.7e+308)
 					return "float64";
+
+				console.error(`Warning: can't find matching Golang number type for '${val}'. Falling back to "any".`)
+				return "any";
 			case "boolean":
 				return "bool";
 			case "object":

json-to-go.test.js

@@ -76,51 +76,51 @@ function test(includeExampleData) {
     {
       input: '{"age": 46}',
       expected:
-        'type AutoGenerated struct {\n\tAge int `json:"age"`\n}\n',
+        'type AutoGenerated struct {\n\tAge int8 `json:"age"`\n}\n',
       expectedWithExample:
-        'type AutoGenerated struct {\n\tAge int `json:"age" example:"46"`\n}\n',
+        'type AutoGenerated struct {\n\tAge int8 `json:"age" example:"46"`\n}\n',
     },
     {
       input: '{"negativeFloat": -1.00}',
       expected:
-        'type AutoGenerated struct {\n\tNegativeFloat float64 `json:"negativeFloat"`\n}\n',
+        'type AutoGenerated struct {\n\tNegativeFloat float32 `json:"negativeFloat"`\n}\n',
       expectedWithExample:
-        'type AutoGenerated struct {\n\tNegativeFloat float64 `json:"negativeFloat" example:"-1.1"`\n}\n',
+        'type AutoGenerated struct {\n\tNegativeFloat float32 `json:"negativeFloat" example:"-1.1"`\n}\n',
     },
     {
       input: '{"zeroFloat": 0.00}',
       expected:
-        'type AutoGenerated struct {\n\tZeroFloat float64 `json:"zeroFloat"`\n}\n',
+        'type AutoGenerated struct {\n\tZeroFloat float32 `json:"zeroFloat"`\n}\n',
       expectedWithExample:
-        'type AutoGenerated struct {\n\tZeroFloat float64 `json:"zeroFloat" example:"0.1"`\n}\n',
+        'type AutoGenerated struct {\n\tZeroFloat float32 `json:"zeroFloat" example:"0.1"`\n}\n',
     },
     {
       input: '{"positiveFloat": 1.00}',
       expected:
-        'type AutoGenerated struct {\n\tPositiveFloat float64 `json:"positiveFloat"`\n}\n',
+        'type AutoGenerated struct {\n\tPositiveFloat float32 `json:"positiveFloat"`\n}\n',
       expectedWithExample:
-        'type AutoGenerated struct {\n\tPositiveFloat float64 `json:"positiveFloat" example:"1.1"`\n}\n',
+        'type AutoGenerated struct {\n\tPositiveFloat float32 `json:"positiveFloat" example:"1.1"`\n}\n',
     },
     {
       input: '{"negativeFloats": [-1.00, -2.00, -3.00]}',
       expected:
-        'type AutoGenerated struct {\n\tNegativeFloats []float64 `json:"negativeFloats"`\n}\n',
+        'type AutoGenerated struct {\n\tNegativeFloats []float32 `json:"negativeFloats"`\n}\n',
       expectedWithExample:
-        'type AutoGenerated struct {\n\tNegativeFloats []float64 `json:"negativeFloats"`\n}\n',
+        'type AutoGenerated struct {\n\tNegativeFloats []float32 `json:"negativeFloats"`\n}\n',
     },
     {
       input: '{"zeroFloats": [0.00, 0.00, 0.00]}',
       expected:
-        'type AutoGenerated struct {\n\tZeroFloats []float64 `json:"zeroFloats"`\n}\n',
+        'type AutoGenerated struct {\n\tZeroFloats []float32 `json:"zeroFloats"`\n}\n',
       expectedWithExample:
-        'type AutoGenerated struct {\n\tZeroFloats []float64 `json:"zeroFloats"`\n}\n',
+        'type AutoGenerated struct {\n\tZeroFloats []float32 `json:"zeroFloats"`\n}\n',
     },
     {
       input: '{"positiveFloats": [1.00, 2.00, 3.00]}',
       expected:
-        'type AutoGenerated struct {\n\tPositiveFloats []float64 `json:"positiveFloats"`\n}\n',
+        'type AutoGenerated struct {\n\tPositiveFloats []float32 `json:"positiveFloats"`\n}\n',
       expectedWithExample:
-        'type AutoGenerated struct {\n\tPositiveFloats []float64 `json:"positiveFloats"`\n}\n',
+        'type AutoGenerated struct {\n\tPositiveFloats []float32 `json:"positiveFloats"`\n}\n',
     },
     {
       input: '{"topLevel": { "secondLevel": "exampleDataHere"} }',
@@ -162,6 +162,7 @@ function testFiles() {
   const testCases = [
     "duplicate-top-level-structs",
     "double-nested-objects",
+    "supported-number-types",
   ];
 
   for (const testCase of testCases) {

tests/double-nested-objects.go

@@ -7,13 +7,13 @@ type Type struct {
 	Long string `json:"long"`
 }
 type First struct {
-	ID int `json:"id"`
+	ID int8 `json:"id"`
 	Type Type `json:"type"`
 }
 type SecondType struct {
 	Long string `json:"long"`
 }
 type Second struct {
-	ID int `json:"id"`
+	ID int8 `json:"id"`
 	SecondType SecondType `json:"type"`
 }

tests/duplicate-top-level-structs.go

@@ -5,7 +5,7 @@ type AutoGenerated struct {
 }
 type Identifier struct {
 	Type string `json:"type"`
-	ID int `json:"id"`
+	ID int16 `json:"id"`
 }
 type Region struct {
 	Identifier Identifier `json:"identifier"`
@@ -20,11 +20,11 @@ type Municipality struct {
 }
 type Postal struct {
 	Type string `json:"type"`
-	ID int `json:"id"`
+	ID int8 `json:"id"`
 }
 type Road struct {
 	Name string `json:"name"`
-	ID int `json:"id"`
+	ID int8 `json:"id"`
 }
 type BuildingIdentifier struct {
 	Postal Postal `json:"postal"`

tests/supported-number-types.go

@@ -0,0 +1,17 @@
+type AutoGenerated struct {
+	Basedonscience bool `json:"basedonscience"`
+	SecondsPerYear float32 `json:"seconds per year"`
+	AgeOfTheUniverse AgeOfTheUniverse `json:"age of the universe"`
+	BasicallyInfinity any `json:"basically infinity"`
+	Date string `json:"date"`
+}
+type AgeOfTheUniverse struct {
+	InPlanckTime float64 `json:"in planck time"`
+	InVeryPreciseMilliseconds float64 `json:"in very precise milliseconds"`
+	InMilliseconds float32 `json:"in milliseconds"`
+	InSeconds int64 `json:"in seconds"`
+	InYears int64 `json:"in years"`
+	InMillenia int32 `json:"in millenia"`
+	InMegaannums int16 `json:"in megaannums"`
+	InGalacticYears int8 `json:"in galactic years"`
+}

tests/supported-number-types.json

@@ -0,0 +1,16 @@
+{
+	"basedonscience": true,
+	"seconds per year": 3.6524219e+2,
+	"age of the universe": {
+			"in planck time": 8.0718985e+60,
+			"in very precise milliseconds": 4.35075327952992e+20,
+			"in milliseconds": 4.3507532e+20,
+			"in seconds": 4.35075327952992e+17,
+			"in years": 13787000000,
+			"in millenia": 13787000,
+			"in megaannums": 13787,
+			"in galactic years": 60
+	},
+	"basically infinity": 4.361170766e+400,
+	"date": "2024-07-25"
+}