Infer type schema (#514)

* Infer type schema (#4)


* Added type inference

* Test cases with tsd

* Allow manual inference

* Restored index.js

* Restore unwanted files

* Removed json-schema-to-ts

Author: Daniele Fedeli

index.d.ts

@@ -1,4 +1,5 @@
 import Ajv, { Options as AjvOptions } from "ajv"
+
 declare namespace build {
   interface BaseSchema {
     /**
@@ -189,13 +190,13 @@ interface StandaloneOption extends build.Options {
 declare function build(schema: build.AnySchema, options: DebugOption): { code: string, ajv: Ajv };
 declare function build(schema: build.AnySchema, options: DeprecateDebugOption): { code: string, ajv: Ajv };
 declare function build(schema: build.AnySchema, options: StandaloneOption): string;
-declare function build(schema: build.AnySchema, options?: build.Options): (doc: any) => any;
-declare function build(schema: build.StringSchema, options?: build.Options): (doc: string) => string;
-declare function build(schema: build.IntegerSchema | build.NumberSchema, options?: build.Options): (doc: number) => string;
-declare function build(schema: build.NullSchema, options?: build.Options): (doc: null) => "null";
-declare function build(schema: build.BooleanSchema, options?: build.Options): (doc: boolean) => string;
-declare function build(schema: build.ArraySchema | build.TupleSchema, options?: build.Options): (doc: any[]) => string;
-declare function build(schema: build.ObjectSchema, options?: build.Options): (doc: object) => string;
-declare function build(schema: build.Schema, options?: build.Options): (doc: object | any[] | string | number | boolean | null) => string;
+declare function build(schema: build.AnySchema, options?: build.Options): <TDoc = any>(doc: TDoc) => any;
+declare function build(schema: build.StringSchema, options?: build.Options): <TDoc extends string = string>(doc: TDoc) => string;
+declare function build(schema: build.IntegerSchema | build.NumberSchema, options?: build.Options): <TDoc extends number = number>(doc: TDoc) => string;
+declare function build(schema: build.NullSchema, options?: build.Options): <TDoc extends null = null>(doc: TDoc) => "null";
+declare function build(schema: build.BooleanSchema, options?: build.Options): <TDoc extends boolean = boolean>(doc: TDoc) => string;
+declare function build(schema: build.ArraySchema | build.TupleSchema, options?: build.Options): <TDoc extends any[]= any[]>(doc: TDoc) => string;
+declare function build(schema: build.ObjectSchema, options?: build.Options): <TDoc extends object = object>(doc: TDoc) => string;
+declare function build(schema: build.Schema, options?: build.Options): <TDoc = object | any[] | string | number | boolean | null> (doc: TDoc) => string;
 
 export = build;

package.json

@@ -11,7 +11,7 @@
     "benchmark": "node ./benchmark/bench-cmp-lib.js",
     "lint:fix": "standard --fix",
     "test:lint": "standard",
-    "test:typescript": "tsc --project ./test/types/tsconfig.json",
+    "test:typescript": "tsc --project ./test/types/tsconfig.json && tsd",
     "test:unit": "tap -J test/*.test.js test/**/*.test.js",
     "test": "npm run test:lint && npm run test:unit && npm run test:typescript"
   },
@@ -45,6 +45,7 @@
     "simple-git": "^3.7.1",
     "standard": "^17.0.0",
     "tap": "^16.0.1",
+    "tsd": "^0.22.0",
     "typescript": "^4.0.2",
     "webpack": "^5.40.0"
   },
@@ -61,5 +62,8 @@
       "schema-validator.js"
     ]
   },
-  "runkitExampleFilename": "./examples/example.js"
+  "runkitExampleFilename": "./examples/example.js",
+  "tsd": {
+    "directory": "test/types"
+  }
 }

test/types/schema-inference.test-d.ts

@@ -0,0 +1,48 @@
+import { expectError } from "tsd";
+import build from "../..";
+
+// With inference
+interface Schema {
+  id: string;
+  a?: number;
+}
+
+const stringify3 = build({
+  type: "object",
+  properties: { a: { type: "string" } },
+});
+stringify3<Schema>({ id: "123" });
+stringify3<Schema>({ a: 123, id: "123" });
+expectError(stringify3<Schema>({ anotherOne: "bar" }));
+expectError(stringify3<Schema>({ a: "bar" }));
+
+// Without inference
+const stringify4 = build({
+  type: "object",
+  properties: { a: { type: "string" } },
+});
+stringify4({ id: "123" });
+stringify4({ a: 123, id: "123" });
+stringify4({ anotherOne: "bar" });
+stringify4({ a: "bar" });
+
+// Without inference - string type
+const stringify5 = build({
+  type: "string",
+});
+stringify5("foo");
+expectError(stringify5({ id: "123" }));
+
+// Without inference - null type
+const stringify6 = build({
+  type: "null",
+});
+stringify6(null);
+expectError(stringify6("a string"));
+
+// Without inference - boolean type
+const stringify7 = build({
+  type: "boolean",
+});
+stringify7(true);
+expectError(stringify7("a string"));