Add pure annotation to json import when stringified

Since Vite 6, a json import over 10kB is stringified by default.

Current implementation would add a JSON.parse() call that would not be tree shaken

packages/vite/src/node/__tests__/plugins/json.spec.ts

@@ -62,7 +62,7 @@ describe('transform', () => {
       false,
     )
     expect(actualSmall).toMatchInlineSnapshot(
-      `"export default JSON.parse("[{\\"a\\":1,\\"b\\":2}]")"`,
+      `"export default /* #__PURE__ */ JSON.parse("[{\\"a\\":1,\\"b\\":2}]")"`,
     )
   })
 
@@ -122,7 +122,7 @@ describe('transform', () => {
       false,
     )
     expect(actualDev).toMatchInlineSnapshot(
-      `"export default JSON.parse("{\\"a\\":1,\\n\\"🫠\\": \\"\\",\\n\\"const\\": false}")"`,
+      `"export default /* #__PURE__ */ JSON.parse("{\\"a\\":1,\\n\\"🫠\\": \\"\\",\\n\\"const\\": false}")"`,
     )
 
     const actualBuild = transform(
@@ -131,7 +131,7 @@ describe('transform', () => {
       true,
     )
     expect(actualBuild).toMatchInlineSnapshot(
-      `"export default JSON.parse("{\\"a\\":1,\\"🫠\\":\\"\\",\\"const\\":false}")"`,
+      `"export default /* #__PURE__ */ JSON.parse("{\\"a\\":1,\\"🫠\\":\\"\\",\\"const\\":false}")"`,
     )
   })
 

packages/vite/src/node/plugins/json.ts

@@ -87,7 +87,7 @@ export function jsonPlugin(
             }
 
             return {
-              code: `export default JSON.parse(${JSON.stringify(json)})`,
+              code: `export default /* #__PURE__ */ JSON.parse(${JSON.stringify(json)})`,
               map: { mappings: '' },
             }
           }