Added coerce support (#18)

* Add coerce

* fix: fix tests, use object.assign for adding coerce

src/dezerialize.ts

@@ -117,7 +117,7 @@ type DezerializersMap = {
 };
 const dezerializers = {
   number: (shape) => {
-    let n = z.number();
+    let n = shape.coerce ? z.coerce.number() : z.number();
     if (shape.min !== undefined) {
       n = shape.minInclusive ? n.min(shape.min) : n.gt(shape.min);
     }
@@ -136,7 +136,7 @@ const dezerializers = {
     return n;
   },
   string: (shape) => {
-    let s = z.string();
+    let s = shape.coerce ? z.coerce.string() : z.string();
     if (shape.min !== undefined) {
       s = s.min(shape.min);
     }
@@ -170,10 +170,10 @@ const dezerializers = {
 
     return s;
   },
-  boolean: () => z.boolean(),
+  boolean: (shape) => shape.coerce ? z.coerce.boolean() : z.boolean(),
   nan: () => z.nan(),
   bigInt: (shape) => {
-    let i = z.bigint();
+    let i = shape.coerce ? z.coerce.bigint() : z.bigint();
     if (shape.min !== undefined) {
       i = shape.minInclusive ? i.min(shape.min) : i.gt(shape.min);
     }
@@ -186,7 +186,7 @@ const dezerializers = {
     return i;
   },
   date: (shape) => {
-    let i = z.date();
+    let i = shape.coerce ? z.coerce.date() : z.date();
     if (shape.min !== undefined) {
       i = i.min(new Date(shape.min));
     }

src/index.test.ts

@@ -404,3 +404,14 @@ test("discriminated union", () => {
     reach: 42,
   });
 });
+
+test("coerce", () => {
+  const schema = z.coerce.number();
+  expect(schema.parse("42")).toEqual(42);
+  const shape = zerialize(schema);
+  expect(shape).toEqual({
+    type: "number",
+    coerce: true,
+  });
+  expect(dezerialize(shape as SzType).parse("42")).toEqual(42);
+});

src/types.ts

@@ -2,6 +2,7 @@ import { ValueOf } from "type-fest";
 
 export type SzNumber = {
   type: "number";
+  coerce?: boolean;
   min?: number;
   max?: number;
   minInclusive?: boolean;
@@ -12,6 +13,7 @@ export type SzNumber = {
 };
 export type SzBigInt = {
   type: "bigInt";
+  coerce?: boolean;
   min?: bigint;
   max?: bigint;
   minInclusive?: boolean;
@@ -31,6 +33,7 @@ export const STRING_KINDS = new Set([
 
 export type SzString = {
   type: "string";
+  coerce?: boolean;
   min?: number;
   max?: number;
   length?: number;
@@ -59,11 +62,12 @@ export type SzString = {
 
 export type SzDate = {
   type: "date";
+  coerce?: boolean;
   min?: number;
   max?: number;
 };
 
-export type SzBoolean = { type: "boolean" };
+export type SzBoolean = { type: "boolean"; coerce?: boolean };
 export type SzNaN = { type: "nan" };
 export type SzUndefined = { type: "undefined" };
 export type SzNull = { type: "null" };

src/zerialize.ts

@@ -167,7 +167,10 @@ const zerializers = {
       }),
       {}
     );
-    return { type: "number", ...checks };
+    return Object.assign(
+      { type: "number", ...checks },
+      def.coerce ? { coerce: true } : {}
+    );
   },
   ZodString: (def) => {
     const checks = def.checks.reduce(
@@ -209,9 +212,13 @@ const zerializers = {
       }),
       {}
     );
-    return { type: "string", ...checks };
+    return Object.assign(
+      { type: "string", ...checks },
+      def.coerce ? { coerce: true } : {}
+    );
   },
-  ZodBoolean: () => ({ type: "boolean" }),
+  ZodBoolean: (def) =>
+    Object.assign({ type: "boolean" }, def.coerce ? { coerce: true } : {}),
   ZodNaN: () => ({ type: "nan" }),
   ZodBigInt: (def) => {
     const checks = def.checks.reduce(
@@ -236,7 +243,10 @@ const zerializers = {
       }),
       {}
     );
-    return { type: "bigInt", ...checks };
+    return Object.assign(
+      { type: "bigInt", ...checks },
+      def.coerce ? { coerce: true } : {}
+    );
   },
   ZodDate: (def) => {
     const checks = def.checks.reduce(
@@ -253,7 +263,10 @@ const zerializers = {
       }),
       {}
     );
-    return { type: "date", ...checks };
+    return Object.assign(
+      { type: "date", ...checks },
+      def.coerce ? { coerce: true } : {}
+    );
   },
   ZodUndefined: () => ({ type: "undefined" }),
   ZodNull: () => ({ type: "null" }),