Require TypeScript 4.1 and add strongly-typed TypeScript types (#80)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

index.d.ts

@@ -1,3 +1,5 @@
+import {Get} from 'type-fest';
+
 declare const dotProp: {
 	/**
 	Get the value of the property at the given path.
@@ -23,15 +25,11 @@ declare const dotProp: {
 	//=> 'unicorn'
 	```
 	*/
-	get<T>(
-		object: {[key: string]: any} | undefined,
-		path: string
-	): T | undefined;
-	get<T>(
-		object: {[key: string]: any} | undefined,
-		path: string,
-		defaultValue: T
-	): T;
+	get: <ObjectType, PathType extends string, DefaultValue = undefined>(
+		object: ObjectType,
+		path: PathType,
+		defaultValue?: DefaultValue
+	) => ObjectType extends Record<string, unknown> ? (Get<ObjectType, PathType> extends unknown ? DefaultValue : Get<ObjectType, PathType>) : undefined; // TODO: When adding array index support (https://github.com/sindresorhus/dot-prop/issues/71) add ` | unknown[]` after `Record<string, unknown>`
 
 	/**
 	Set the property at the given path to the given value.
@@ -59,11 +57,11 @@ declare const dotProp: {
 	//=> {foo: {bar: 'b', baz: 'x'}}
 	```
 	*/
-	set<T extends {[key: string]: any}>(
-		object: T,
+	set: <ObjectType extends {[key: string]: any}>(
+		object: ObjectType,
 		path: string,
 		value: unknown
-	): T;
+	) => ObjectType;
 
 	/**
 	Check whether the property at the given path exists.
@@ -79,7 +77,7 @@ declare const dotProp: {
 	//=> true
 	```
 	*/
-	has(object: {[key: string]: any} | undefined, path: string): boolean;
+	has: (object: {[key: string]: any} | undefined, path: string) => boolean;
 
 	/**
 	Delete the property at the given path.
@@ -103,7 +101,7 @@ declare const dotProp: {
 	//=> {foo: {bar: {y: 'x'}}}
 	```
 	*/
-	delete(object: {[key: string]: any}, path: string): boolean;
+	delete: (object: {[key: string]: any}, path: string) => boolean;
 };
 
 export = dotProp;

index.test-d.ts

@@ -1,13 +1,12 @@
 import {expectType, expectAssignable} from 'tsd';
 import dotProp = require('.');
 
-expectType<unknown>(dotProp.get({foo: {bar: 'unicorn'}}, 'foo.bar'));
-expectType<string | undefined>(dotProp.get<string>({foo: {bar: 'unicorn'}}, 'foo.bar'));
-expectType<unknown>(dotProp.get({foo: {bar: 'a'}}, 'foo.notDefined.deep'));
+expectType<string>(dotProp.get({foo: {bar: 'unicorn'}}, 'foo.bar'));
+expectType<undefined>(dotProp.get({foo: {bar: 'a'}}, 'foo.notDefined.deep'));
 expectAssignable<string>(
 	dotProp.get({foo: {bar: 'a'}}, 'foo.notDefined.deep', 'default value')
 );
-expectType<unknown>(
+expectType<string>(
 	dotProp.get({foo: {'dot.dot': 'unicorn'}}, 'foo.dot\\.dot')
 );
 

package.json

@@ -35,17 +35,13 @@
 		"dotty"
 	],
 	"dependencies": {
-		"is-obj": "^2.0.0"
+		"is-obj": "^2.0.0",
+		"type-fest": "^1.0.0"
 	},
 	"devDependencies": {
 		"ava": "^2.1.0",
 		"benchmark": "^2.1.4",
-		"tsd": "^0.13.1",
+		"tsd": "^0.14.0",
 		"xo": "^0.33.1"
-	},
-	"xo": {
-		"rules": {
-			"@typescript-eslint/method-signature-style": "off"
-		}
 	}
 }