fix(json-type): 🐛 make "map" JSON codegen work

Author: streamich

src/json-type/codegen/json/__tests__/json.spec.ts

@@ -127,6 +127,16 @@ describe('"map" type', () => {
     exec(type, {a: 1, b: 2, c: 3});
   });
 
+  test('serializes empty map', () => {
+    const type = s.Map(s.num);
+    exec(type, {});
+  });
+
+  test('serializes a map with a single key', () => {
+    const type = s.Map(s.num);
+    exec(type, {'0': 0});
+  });
+
   test('serializes a map in a map', () => {
     const type = s.Map(s.Map(s.bool));
     exec(type, {a: {b: true}});

src/json-type/type/TypeBuilder.ts

@@ -186,6 +186,8 @@ export class TypeBuilder {
           ),
         ).options(node);
       }
+      case 'map':
+        return this.Map(this.import(node.type), node);
       case 'const':
         return this.Const(node.value).options(node);
       case 'or':

src/json-type/type/classes.ts

@@ -1935,13 +1935,13 @@ export class MapType<T extends Type> extends AbstractType<schema.MapSchema<Schem
     const r = ctx.codegen.var(value.use());
     const rKeys = ctx.codegen.var(`Object.keys(${r})`);
     const rLength = ctx.codegen.var(`${rKeys}.length`);
-    const rKey = ctx.codegen.r();
-    const rValue = ctx.codegen.r();
+    const rKey = ctx.codegen.var();
     ctx.codegen.if(`${rLength}`, () => {
-      ctx.js(`s += asString(${rKeys}[i]) + ':';`);
+      ctx.js(`${rKey} = ${rKeys}[0];`);
+      ctx.js(`s += asString(${rKey}) + ':';`);
       this.type.codegenJsonTextEncoder(ctx, new JsExpression(() => `${r}[${rKey}]`));
     });
-    ctx.js(`for (var ${rKey}, ${rValue}, i = 1; i < ${rLength}; i++) {`);
+    ctx.js(`for (var i = 1; i < ${rLength}; i++) {`);
     ctx.js(`${rKey} = ${rKeys}[i];`);
     ctx.js(`s += ',' + asString(${rKey}) + ':';`);
     this.type.codegenJsonTextEncoder(ctx, new JsExpression(() => `${r}[${rKey}]`));