Allow specifying whether targetValue should be recursed (#29)

index.d.ts

@@ -7,7 +7,11 @@ declare namespace mapObject {
 		sourceKey: keyof SourceObjectType,
 		sourceValue: SourceObjectType[keyof SourceObjectType],
 		source: SourceObjectType
-	) => [MappedObjectKeyType, MappedObjectValueType];
+	) => [
+		targetKey: MappedObjectKeyType,
+		targetValue: MappedObjectValueType,
+		mapperOptions?: mapObject.MapperOptions
+	];
 
 	interface Options {
 		/**
@@ -32,6 +36,15 @@ declare namespace mapObject {
 	interface TargetOptions<TargetObjectType extends {[key: string]: any}> extends Options {
 		target: TargetObjectType;
 	}
+
+	interface MapperOptions {
+		/**
+		Whether `targetValue` should be recursed. Requires `deep: true`.
+
+		@default true
+		*/
+		shouldRecurse?: boolean;
+	}
 }
 
 /**

index.js

@@ -31,9 +31,9 @@ const mapObject = (object, mapper, options, isSeen = new WeakMap()) => {
 	}
 
 	for (const [key, value] of Object.entries(object)) {
-		let [newKey, newValue] = mapper(key, value, object);
+		let [newKey, newValue, {shouldRecurse = true} = {}] = mapper(key, value, object);
 
-		if (options.deep && isObjectCustom(newValue)) {
+		if (options.deep && shouldRecurse && isObjectCustom(newValue)) {
 			newValue = Array.isArray(newValue) ?
 				mapArray(newValue) :
 				mapObject(newValue, mapper, options, isSeen);

index.test-d.ts

@@ -32,3 +32,5 @@ const object3 = mapObject({foo: 'bar'}, (key, value) => [value, key], {
 });
 expectType<{[key: string]: unknown}>(object3);
 expectType<'baz'>(object3.bar);
+
+mapObject({foo: 'bar'}, (key, value) => [value, key, {shouldRecurse: false}]);

package.json

@@ -36,7 +36,7 @@
 	],
 	"devDependencies": {
 		"ava": "^2.0.0",
-		"tsd": "^0.7.3",
+		"tsd": "^0.14.0",
 		"xo": "^0.24.0"
 	}
 }

readme.md

@@ -32,12 +32,18 @@ Source object to copy properties from.
 
 #### mapper
 
-Type: `Function`
+Type: `(sourceKey, sourceValue, source) => [targetKey, targetValue, mapperOptions?]`
 
 Mapping function.
 
-- It has signature `mapper(sourceKey, sourceValue, source)`.
-- It must return a two item array: `[targetKey, targetValue]`.
+##### mapperOptions
+
+###### shouldRecurse
+
+Type: `boolean`\
+Default: `true`
+
+Whether `targetValue` should be recursed. Requires `deep: true`.
 
 #### options
 

test.js

@@ -47,6 +47,47 @@ test('deep option', t => {
 	t.deepEqual(actual, expected);
 });
 
+test('shouldRecurse mapper option', t => {
+	const object = {
+		one: 1,
+		object: {
+			two: 2,
+			three: 3
+		},
+		array: [
+			{
+				four: 4
+			},
+			5
+		]
+	};
+
+	const expected = {
+		one: 2,
+		object: {
+			two: 2,
+			three: 3
+		},
+		array: [
+			{
+				four: 8
+			},
+			5
+		]
+	};
+
+	const mapper = (key, value) => {
+		if (key === 'object') {
+			return [key, value, {shouldRecurse: false}];
+		}
+
+		return [key, typeof value === 'number' ? value * 2 : value];
+	};
+
+	const actual = mapObject(object, mapper, {deep: true});
+	t.deepEqual(actual, expected);
+});
+
 test('nested arrays', t => {
 	const object = {
 		array: [