Add z.string().json(...) helper (colinhacks#3109)

* Add z.string().json(...) helper * use parseAsync + await expect(...).rejects * make it work in deno * Add overload --------- Co-authored-by: Misha Kaletsky <[email protected]> Co-authored-by: Colin McDonnell <[email protected]>
ytsunekawa · May 3, 2024 · 941965b · 941965b
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diff --git a/README.md b/README.md
@@ -75,6 +75,7 @@
   - [Dates](#dates)
   - [Times](#times)
   - [IP addresses](#ip-addresses)
+  - [JSON](#json)
 - [Numbers](#numbers)
 - [BigInts](#bigints)
 - [NaNs](#nans)
@@ -783,6 +784,44 @@ const ipv6 = z.string().ip({ version: "v6" });
 ipv6.parse("192.168.1.1"); // fail
 ```
 
+### JSON
+
+The `z.string().json(...)` method parses strings as JSON, then [pipes](#pipe) the result to another specified schema.
+
+```ts
+const Env = z.object({
+  API_CONFIG: z.string().json(
+    z.object({
+      host: z.string(),
+      port: z.number().min(1000).max(2000),
+    })
+  ),
+  SOME_OTHER_VALUE: z.string(),
+});
+
+const env = Env.parse({
+  API_CONFIG: '{ "host": "example.com", "port": 1234 }',
+  SOME_OTHER_VALUE: "abc123",
+});
+
+env.API_CONFIG.host; // returns parsed value
+```
+
+If invalid JSON is encountered, the syntax error will be wrapped and put into a parse error:
+
+```ts
+const env = Env.safeParse({
+  API_CONFIG: "not valid json!",
+  SOME_OTHER_VALUE: "abc123",
+});
+
+if (!env.success) {
+  console.log(env.error); // ... Unexpected token n in JSON at position 0 ...
+}
+```
+
+This is recommended over using `z.string().transform(s => JSON.parse(s))`, since that will not catch parse errors, even when using `.safeParse`.
+
 ## Numbers
 
 You can customize certain error messages when creating a number schema.

diff --git a/deno/lib/README.md b/deno/lib/README.md
@@ -75,6 +75,7 @@
   - [Dates](#dates)
   - [Times](#times)
   - [IP addresses](#ip-addresses)
+  - [JSON](#json)
 - [Numbers](#numbers)
 - [BigInts](#bigints)
 - [NaNs](#nans)
@@ -783,6 +784,44 @@ const ipv6 = z.string().ip({ version: "v6" });
 ipv6.parse("192.168.1.1"); // fail
 ```
 
+### JSON
+
+The `z.string().json(...)` method parses strings as JSON, then [pipes](#pipe) the result to another specified schema.
+
+```ts
+const Env = z.object({
+  API_CONFIG: z.string().json(
+    z.object({
+      host: z.string(),
+      port: z.number().min(1000).max(2000),
+    })
+  ),
+  SOME_OTHER_VALUE: z.string(),
+});
+
+const env = Env.parse({
+  API_CONFIG: '{ "host": "example.com", "port": 1234 }',
+  SOME_OTHER_VALUE: "abc123",
+});
+
+env.API_CONFIG.host; // returns parsed value
+```
+
+If invalid JSON is encountered, the syntax error will be wrapped and put into a parse error:
+
+```ts
+const env = Env.safeParse({
+  API_CONFIG: "not valid json!",
+  SOME_OTHER_VALUE: "abc123",
+});
+
+if (!env.success) {
+  console.log(env.error); // ... Unexpected token n in JSON at position 0 ...
+}
+```
+
+This is recommended over using `z.string().transform(s => JSON.parse(s))`, since that will not catch parse errors, even when using `.safeParse`.
+
 ## Numbers
 
 You can customize certain error messages when creating a number schema.

diff --git a/deno/lib/ZodError.ts b/deno/lib/ZodError.ts
@@ -93,7 +93,11 @@ export interface ZodInvalidDateIssue extends ZodIssueBase {
 export type StringValidation =
   | "email"
   | "url"
+<<<<<<< HEAD
   | "jwt"
+=======
+  | "json"
+>>>>>>> c5a2690 (Add z.string().json(...) helper)
   | "emoji"
   | "uuid"
   | "nanoid"

diff --git a/deno/lib/__tests__/json.test.ts b/deno/lib/__tests__/json.test.ts
@@ -0,0 +1,102 @@
+// @ts-ignore TS6133
+import { expect } from "https://deno.land/x/[email protected]/mod.ts";
+const test = Deno.test;
+
+import * as z from "../index.ts";
+
+// @ts-ignore TS2304
+const isDeno = typeof Deno === "object";
+
+test("overload types", () => {
+  const schema = z.string().json();
+  z.util.assertEqual<typeof schema, z.ZodString>(true);
+  const schema2 = z.string().json(z.number());
+  z.util.assertEqual<
+    typeof schema2,
+    z.ZodPipeline<z.ZodEffects<z.ZodString, any, string>, z.ZodNumber>
+  >(true);
+  const r2 = schema2.parse("12");
+  z.util.assertEqual<number, typeof r2>(true);
+});
+test("parse string to json", async () => {
+  const Env = z.object({
+    myJsonConfig: z.string().json(z.object({ foo: z.number() })),
+    someOtherValue: z.string(),
+  });
+
+  expect(
+    Env.parse({
+      myJsonConfig: '{ "foo": 123 }',
+      someOtherValue: "abc",
+    })
+  ).toEqual({
+    myJsonConfig: { foo: 123 },
+    someOtherValue: "abc",
+  });
+
+  const invalidValues = Env.safeParse({
+    myJsonConfig: '{"foo": "not a number!"}',
+    someOtherValue: null,
+  });
+  expect(JSON.parse(JSON.stringify(invalidValues))).toEqual({
+    success: false,
+    error: {
+      name: "ZodError",
+      issues: [
+        {
+          code: "invalid_type",
+          expected: "number",
+          received: "string",
+          path: ["myJsonConfig", "foo"],
+          message: "Expected number, received string",
+        },
+        {
+          code: "invalid_type",
+          expected: "string",
+          received: "null",
+          path: ["someOtherValue"],
+          message: "Expected string, received null",
+        },
+      ],
+    },
+  });
+
+  const invalidJsonSyntax = Env.safeParse({
+    myJsonConfig: "This is not valid json",
+    someOtherValue: null,
+  });
+  expect(JSON.parse(JSON.stringify(invalidJsonSyntax))).toEqual({
+    success: false,
+    error: {
+      name: "ZodError",
+      issues: [
+        {
+          code: "invalid_string",
+          validation: "json",
+          message: "Invalid json",
+          path: ["myJsonConfig"],
+        },
+        {
+          code: "invalid_type",
+          expected: "string",
+          received: "null",
+          path: ["someOtherValue"],
+          message: "Expected string, received null",
+        },
+      ],
+    },
+  });
+});
+
+test("no argument", () => {
+  const schema = z.string().json();
+  z.util.assertEqual<typeof schema, z.ZodString>(true);
+  z.string().json().parse(`{}`);
+  z.string().json().parse(`null`);
+  z.string().json().parse(`12`);
+  z.string().json().parse(`{ "test": "test"}`);
+  expect(() => z.string().json().parse(`asdf`)).toThrow();
+  expect(() => z.string().json().parse(`{ "test": undefined }`)).toThrow();
+  expect(() => z.string().json().parse(`{ "test": 12n }`)).toThrow();
+  expect(() => z.string().json().parse(`{ test: "test" }`)).toThrow();
+});
diff --git a/deno/lib/types.ts b/deno/lib/types.ts
@@ -569,6 +569,7 @@ export type ZodStringCheck =
       precision: number | null;
       message?: string;
     }
+<<<<<<< HEAD
   | {
       kind: "date";
       // withDate: true;
@@ -582,6 +583,10 @@ export type ZodStringCheck =
   | { kind: "duration"; message?: string }
   | { kind: "ip"; version?: IpVersion; message?: string }
   | { kind: "base64"; message?: string };
+=======
+  | { kind: "ip"; version?: IpVersion; message?: string }
+  | { kind: "json"; message?: string };
+>>>>>>> ca9c3e1 (Add overload)
 
 export interface ZodStringDef extends ZodTypeDef {
   checks: ZodStringCheck[];
@@ -1019,12 +1024,23 @@ export class ZodString extends ZodType<string, ZodStringDef, string> {
           });
           status.dirty();
         }
+<<<<<<< HEAD
       } else if (check.kind === "base64") {
         if (!base64Regex.test(input.data)) {
           ctx = this._getOrReturnCtx(input, ctx);
           addIssueToContext(ctx, {
             validation: "base64",
             code: ZodIssueCode.invalid_string,
+=======
+      } else if (check.kind === "json") {
+        try {
+          JSON.parse(input.data);
+        } catch (err) {
+          ctx = this._getOrReturnCtx(input, ctx);
+          addIssueToContext(ctx, {
+            code: ZodIssueCode.invalid_string,
+            validation: "json",
+>>>>>>> ca9c3e1 (Add overload)
             message: check.message,
           });
           status.dirty();
@@ -1199,6 +1215,29 @@ export class ZodString extends ZodType<string, ZodStringDef, string> {
     });
   }
 
+  json(message?: errorUtil.ErrMessage): this;
+  json<T extends ZodTypeAny>(
+    pipeTo: T
+  ): ZodPipeline<ZodEffects<this, any, input<this>>, T>;
+  json(input?: errorUtil.ErrMessage | ZodTypeAny) {
+    if (!(input instanceof ZodType)) {
+      return this._addCheck({ kind: "json", ...errorUtil.errToObj(input) });
+    }
+    const schema = this.transform((val, ctx) => {
+      try {
+        return JSON.parse(val);
+      } catch (error: unknown) {
+        ctx.addIssue({
+          code: ZodIssueCode.invalid_string,
+          validation: "json",
+          // message: (error as Error).message,
+        });
+        return NEVER;
+      }
+    });
+    return input ? schema.pipe(input) : schema;
+  }
+
   min(minLength: number, message?: errorUtil.ErrMessage) {
     return this._addCheck({
       kind: "min",

diff --git a/playground.ts b/playground.ts
@@ -1,3 +1,3 @@
 import { z } from "./src/index";
 
-z.string().parse("asdf");
+z;
diff --git a/src/ZodError.ts b/src/ZodError.ts
@@ -94,6 +94,7 @@ export type StringValidation =
   | "email"
   | "url"
   | "jwt"
+  | "json"
   | "emoji"
   | "uuid"
   | "nanoid"