fix(schema-utils): add autocast string -> number

packages/schema-utils/src/index.ts

@@ -5,6 +5,7 @@ import { Mixin } from 'ts-mixer';
 
 import { ArrayBufferBuilder, BufferBuilder, KeyofEnumBuilder, UintBuilder } from './custom-types';
 import { InvalidParameter } from './errors';
+import { setDeepValue } from './utils';
 
 class CustomTypeBuilder extends Mixin(
     JavaScriptTypeBuilder,
@@ -69,6 +70,17 @@ export function Assert<T extends TSchema>(schema: T, value: unknown): asserts va
         } else if (error.type === ValueErrorType.Union) {
             // Drill down into the union
             FindErrorInUnion(error);
+        } else if (error.type === ValueErrorType.Number && typeof error.value === 'string') {
+            // String instead of number, try to autocast
+            const currentValue = error.value;
+            const parsedNumber = Number(currentValue);
+            if (!Number.isNaN(parsedNumber) && currentValue === parsedNumber.toString()) {
+                // Autocast successful
+                const pathParts = error.path.slice(1).split('/');
+                setDeepValue(value, pathParts, parsedNumber);
+            } else {
+                throw new InvalidParameter(error.message, error.path, error.type, error.value);
+            }
         } else {
             throw new InvalidParameter(error.message, error.path, error.type, error.value);
         }

packages/schema-utils/src/utils.ts

@@ -0,0 +1,15 @@
+/**
+ * Sets a value in an object by a path
+ * From https://stackoverflow.com/a/53762921
+ * @param obj object to set value in
+ * @param param path to the value
+ * @param value value to set
+ */
+export function setDeepValue(obj: any, [prop, ...path]: string[], value: any) {
+    if (!path.length) {
+        obj[prop] = value;
+    } else {
+        if (!(prop in obj)) obj[prop] = {};
+        setDeepValue(obj[prop], path, value);
+    }
+}

packages/schema-utils/tests/number-autocast.test.ts

@@ -0,0 +1,23 @@
+import { Type, Assert } from '../src';
+
+describe('number-autocast', () => {
+    it('should string to number if needed', () => {
+        const schema = Type.Object({
+            number: Type.Number(),
+            nested: Type.Object({
+                number: Type.Number(),
+            }),
+        });
+
+        const input = {
+            number: '1',
+            nested: {
+                number: '1',
+            },
+        };
+
+        Assert(schema, input);
+        expect(input.number).toEqual(1);
+        expect(input.nested.number).toEqual(1);
+    });
+});

packages/schema-utils/tests/utils.test.ts

@@ -0,0 +1,21 @@
+import { setDeepValue } from '../src/utils';
+
+describe('setDeepValue', () => {
+    it('sets a deep value in an object', () => {
+        const obj = {};
+        setDeepValue(obj, ['a', 'b', 'c'], 123);
+        expect(obj).toEqual({ a: { b: { c: 123 } } });
+    });
+
+    it('overwrites existing values', () => {
+        const obj = { a: { b: { c: 123 } } };
+        setDeepValue(obj, ['a', 'b', 'c'], 456);
+        expect(obj).toEqual({ a: { b: { c: 456 } } });
+    });
+
+    it('creates intermediate objects if necessary', () => {
+        const obj = {};
+        setDeepValue(obj, ['a', 'b', 'c'], 123);
+        expect(obj).toEqual({ a: { b: { c: 123 } } });
+    });
+});