Added get()

package.json

@@ -66,7 +66,7 @@
     "url": "https://github.com/webdeveric/utils/issues"
   },
   "homepage": "https://github.com/webdeveric/utils/#readme",
-  "packageManager": "pnpm@10.12.4+sha512.5ea8b0deed94ed68691c9bad4c955492705c5eeb8a87ef86bc62c74a26b037b08ff9570f108b2e4dbd1dd1a9186fea925e527f141c648e85af45631074680184",
+  "packageManager": "pnpm@10.13.1+sha512.37ebf1a5c7a30d5fabe0c5df44ee8da4c965ca0c5af3dbab28c3a1681b70a256218d05c81c9c0dcf767ef6b8551eb5b960042b9ed4300c59242336377e01cfad",
   "scripts": {
     "clean": "rimraf ./dist/",
     "prebuild": "pnpm clean",
@@ -87,14 +87,14 @@
   "devDependencies": {
     "@commitlint/config-conventional": "^19.8.1",
     "@commitlint/types": "^19.8.1",
-    "@types/node": "^22.16.0",
+    "@types/node": "^22.16.3",
     "@vitest/coverage-v8": "^3.2.4",
     "@webdeveric/eslint-config-ts": "^0.11.0",
     "@webdeveric/prettier-config": "^0.3.0",
     "commitlint": "^19.8.1",
-    "commitlint-plugin-cspell": "^0.2.0",
-    "conventional-changelog-conventionalcommits": "^9.0.0",
-    "cspell": "^9.1.2",
+    "commitlint-plugin-cspell": "^0.3.0",
+    "conventional-changelog-conventionalcommits": "^9.1.0",
+    "cspell": "^9.1.3",
     "eslint": "^8.57.1",
     "eslint-config-prettier": "^10.1.5",
     "eslint-import-resolver-typescript": "^4.4.4",
@@ -104,9 +104,9 @@
     "lint-staged": "^16.1.2",
     "prettier": "^3.6.2",
     "rimraf": "^6.0.1",
-    "semantic-release": "^24.2.6",
+    "semantic-release": "^24.2.7",
     "typescript": "^5.8.3",
-    "validate-package-exports": "^0.11.0",
+    "validate-package-exports": "^0.12.0",
     "vitest": "^3.2.4"
   },
   "pnpm": {

src/get.ts

@@ -0,0 +1,32 @@
+import { pathParts } from './pathParts.js';
+
+import type { Path, PathValue } from './types/objects.js';
+
+export function get<Input extends object, const InputPath extends Path<Input>>(
+  input: Input,
+  path: InputPath,
+): PathValue<Input, InputPath>;
+
+export function get<const Input extends object, const InputPath extends string>(input: Input, path: InputPath): unknown;
+
+export function get<const Input extends object, const InputPath extends Path<Input> | string>(
+  input: Input,
+  path: InputPath,
+): unknown {
+  if (path === '') {
+    return input;
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  let current: any = input;
+
+  for (const part of pathParts(path)) {
+    if (typeof current === 'object' && current !== null && part in current) {
+      current = current[part];
+    } else {
+      return;
+    }
+  }
+
+  return current;
+}

src/index.ts

@@ -23,6 +23,7 @@ export * from './delayAnimationFrame.js';
 export * from './delayAnimationFrames.js';
 export * from './describeInput.js';
 export * from './escapeRegExp.js';
+export * from './get.js';
 export * from './getDateString.js';
 export * from './getISODateString.js';
 export * from './getMaxValue.js';
@@ -44,6 +45,7 @@ export * from './jsonParse.js';
 export * from './looksLikeURL.js';
 export * from './normalize.js';
 export * from './parseNumber.js';
+export * from './pathParts.js';
 export * from './prefix.js';
 export * from './randomInt.js';
 export * from './redactCredentialsInURL.js';

src/pathParts.ts

@@ -0,0 +1,15 @@
+export function* pathParts(input: PropertyKey): Generator<PropertyKey> {
+  if (typeof input !== 'string') {
+    yield input;
+
+    return;
+  }
+
+  const regexp = /\w+/g;
+
+  const iterator = input.matchAll(regexp);
+
+  for (const part of iterator) {
+    yield part[0];
+  }
+}

src/types/arrays.ts

@@ -13,6 +13,16 @@ export type IfLength<A extends any[], L extends number, T, F> = GetLength<A> ext
 
 export type IfEmpty<A extends any[], T, F> = GetLength<A> extends 0 ? T : F;
 
-export type IfArray<Type, T, F> = Type extends unknown[] ? T : F;
+/**
+ * Check if `Type` is an array (excluding tuples).
+ */
+export type IfArray<Type, T, F> = Type extends readonly unknown[] ? (number extends Type['length'] ? T : F) : F;
+
+export type IsArray<Type> = IfArray<Type, true, false>;
 
 export type NonEmptyArray<Type> = [Type, ...Type[]];
+
+// Arrays and tuples both extends readonly arrays, so we can use the same type guard.
+export type IfArrayLike<Type, T, F> = Type extends readonly unknown[] ? T : F;
+
+export type IsArrayLike<Type> = IfArrayLike<Type, true, false>;

src/types/objects.ts

@@ -1,3 +1,4 @@
+import type { IfArray, IfArrayLike } from './arrays.js';
 import type { Primitive } from './common.js';
 import type { CamelCase } from './strings.js';
 import type { KeyValueTuple } from './tuples.js';
@@ -29,13 +30,13 @@ export type MethodNames<Type, Key extends keyof Type = keyof Type> = Key extends
 
 /**
  * Get keys of `Type` for use in `Path`.
- * Keys should not be method names or symbols.
+ * Keys should not be symbols.
  *
  * @internal
  */
-export type ValidKeys<Type> = Type extends unknown[]
-  ? number
-  : `${Exclude<keyof NonNullable<Type>, symbol | MethodNames<NonNullable<Type>>>}`;
+export type ValidKeys<Type extends object> = object extends Type
+  ? never
+  : Exclude<keyof Type, IfArrayLike<Type, symbol | MethodNames<Type>, symbol>>;
 
 /**
  * Get the possible dot notations for a given `Type`.
@@ -55,7 +56,7 @@ export type ValidKeys<Type> = Type extends unknown[]
  * type ExampleNotation = "job" | "job.title";
  * ```
  */
-export type PathDotNotation<Type, Key extends keyof Type = keyof Type> =
+export type PathDotNotation<Type extends object, Key extends keyof Type = keyof Type> =
   Key extends ValidKeys<Type>
     ? Type[Key] extends Primitive
       ? Key
@@ -78,7 +79,27 @@ export type PathDotNotation<Type, Key extends keyof Type = keyof Type> =
  * type ExampleNotation = "job" | "job.title";
  * ```
  */
-export type Path<Type> = PathDotNotation<NonNullableProperties<Type>, keyof Type> | ValidKeys<Type>;
+export type Path<Type extends object> = PathDotNotation<NonNullableProperties<Type>, keyof Type> | ValidKeys<Type>;
+
+/**
+ * @internal
+ */
+export type MaybeOptional<Type, Optional extends boolean> = Optional extends true ? Type | undefined : Type;
+
+/**
+ * @internal
+ */
+export type GetValueForKey<
+  Type extends object,
+  Key extends PropertyKey,
+  Optional extends boolean = CanBeUndefined<Type, true, false>,
+> = Key extends keyof Type
+  ? MaybeOptional<Type[Key], IfArray<Type, true, Optional>> // array items should always be checked for undefined
+  : Key extends `${infer Index extends number}`
+    ? Index extends keyof Type
+      ? MaybeOptional<Type[Index], IfArray<Type, true, Optional>>
+      : never
+    : never;
 
 /**
  * Get the type for a given dot notation path.
@@ -97,21 +118,17 @@ export type Path<Type> = PathDotNotation<NonNullableProperties<Type>, keyof Type
  * ```
  */
 export type PathValue<
-  Type,
+  Type extends object,
   TargetPath extends Path<Type>,
   Optional extends boolean = CanBeUndefined<Type, true, false>,
 > = TargetPath extends `${infer Key}.${infer Rest}`
-  ? Key extends keyof Type
-    ? Rest extends Path<NonNullable<Type[Key]>>
-      ? PathValue<NonNullable<Type[Key]>, Rest, CanBeUndefined<Type[Key], true, false>>
+  ? GetValueForKey<Type, Key, Optional> extends infer Value
+    ? Rest extends Path<NonNullable<Value>>
+      ? PathValue<NonNullable<Value>, Rest, CanBeUndefined<Value, true, false>>
       : never
     : never
-  : TargetPath extends keyof Type
-    ? Optional extends true
-      ? Type[TargetPath] | undefined
-      : Type[TargetPath]
-    : never;
+  : GetValueForKey<Type, TargetPath, Optional>;
 
-export type PathValues<Type, TargetPaths extends Path<Type>> = {
+export type PathValues<Type extends object, TargetPaths extends Path<Type>> = {
   [TargetPath in TargetPaths as CamelCase<`${TargetPath}`, '.'>]: PathValue<Type, TargetPath>;
 };

src/types/tuples.ts

@@ -10,3 +10,8 @@ export type NumberRangeTuple = RangeTuple<number>;
 export type KeyValueTuple<K extends PropertyKey = PropertyKey, V = unknown> = [key: K, value: V];
 
 export type TupleToArray<T extends any[]> = T[number][];
+
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+export type IfTuple<Type, T, F> = Type extends readonly [...infer _] ? (number extends Type['length'] ? F : T) : F;
+
+export type IsTuple<Type> = IfTuple<Type, true, false>;

test/get.test.ts

@@ -0,0 +1,54 @@
+import { describe, it, expect } from 'vitest';
+
+import { get } from '../src/get.js';
+
+describe('get()', () => {
+  const input = {
+    age: 100_000,
+    name: {
+      first: 'Test',
+      last: 'Testerson',
+    },
+    sayHi(): void {
+      console.log('Hi!');
+    },
+    role: [
+      {
+        job: {
+          title: 'Developer',
+        },
+      },
+    ],
+  };
+
+  it('returns a value from an object', () => {
+    const lastName = get(input, 'name.last');
+    const jobTitle = get(input, 'role.0.job.title');
+
+    expect(lastName).toBe(input.name.last);
+    expect(jobTitle).toBe(input.role[0]?.job.title);
+  });
+
+  it('Returns undefined when path is invalid', () => {
+    const result = get(input, 'role.0.job.nonExistent');
+
+    expect(result).toBeUndefined();
+  });
+
+  it('Handles built in objects', () => {
+    const date = new Date();
+
+    const result = get(date, 'toString');
+
+    // eslint-disable-next-line @typescript-eslint/unbound-method
+    expect(result).toBe(date.toString);
+  });
+
+  it('Empty path returns input', () => {
+    const date = new Date();
+
+    const result = get(date, '');
+
+    expect(result).toBe(date);
+  });
+});

test/pathParts.test.ts

@@ -0,0 +1,26 @@
+import { describe, it, expect } from 'vitest';
+
+import { pathParts } from '../src/pathParts.js';
+
+describe('pathParts()', () => {
+  it.each([
+    ['role.0.job.title', ['role', '0', 'job', 'title']],
+    ['role.0.job.title', ['role', '0', 'job', 'title']],
+    ['role.0.job["title"]', ['role', '0', 'job', 'title']],
+    ['role.0.job[title]', ['role', '0', 'job', 'title']],
+    ['role["0"].job.title', ['role', '0', 'job', 'title']],
+    ['role["0"].job.title', ['role', '0', 'job', 'title']],
+    ['role["0"].job["title"]', ['role', '0', 'job', 'title']],
+    ['role["0"].job[title]', ['role', '0', 'job', 'title']],
+    ['role[0].job.title', ['role', '0', 'job', 'title']],
+    ['role[0].job.title', ['role', '0', 'job', 'title']],
+    ['role[0].job["title"]', ['role', '0', 'job', 'title']],
+    ['role[0].job[title]', ['role', '0', 'job', 'title']],
+  ])('returns an iterator of path parts: %s => %j', (input, expected) => {
+    expect(Array.from(pathParts(input))).toEqual(expected);
+  });
+
+  it('returns input for non-string input', () => {
+    expect(Array.from(pathParts(123))).toEqual([123]);
+  });
+});

test/types/arrays.test-d.ts

@@ -54,7 +54,7 @@ describe('IfEmpty', () => {
 
 describe('IfArray', () => {
   it('returns the true type if the type is an array', () => {
-    expectTypeOf<IfArray<[], 'yes', 'no'>>().toEqualTypeOf<'yes'>();
+    expectTypeOf<IfArray<string[], 'yes', 'no'>>().toEqualTypeOf<'yes'>();
   });
 
   it('returns the false type if the type is not an array', () => {