Add isKeyOf function for checking if a value is a key of an object

cdn/radash.esm.js

@@ -91,6 +91,9 @@ const isNullish = (value) => {
 const isNonNullish = (value) => {
   return value !== null && value !== void 0;
 };
+const isKeyOf = (value, obj) => {
+  return value in obj;
+};
 
 const group = (array, getGroupId) => {
   return array.reduce((acc, item) => {
@@ -943,4 +946,4 @@ const trim = (str, charsToTrim = " ") => {
   return str.replace(regex, "");
 };
 
-export { all, alphabetical, assign, boil, callable, camel, capitalize, chain, clone, cluster, compose, construct, counting, crush, dash, debounce, defer, diff, draw, first, flat, fork, get, group, guard, inRange, intersects, invert, isArray, isDate, isEmpty, isEqual, isFloat, isFunction, isInt, isNonNullish, isNullish, isNumber, isObject, isPrimitive, isPromise, isString, isSymbol, iterate, keys, last, list, listify, lowerize, map, mapEntries, mapKeys, mapValues, max, memo, merge, min, objectify, omit, parallel, partial, partob, pascal, pick, proxied, random, range, reduce, replace, replaceOrAppend, retry, select, series, set, shake, shift, shuffle, sift, sleep, snake, sort, sum, template, throttle, title, toFloat, toInt, toggle, trim, tryit as try, tryit, uid, unique, upperize, zip, zipToObject };
+export { all, alphabetical, assign, boil, callable, camel, capitalize, chain, clone, cluster, compose, construct, counting, crush, dash, debounce, defer, diff, draw, first, flat, fork, get, group, guard, inRange, intersects, invert, isArray, isDate, isEmpty, isEqual, isFloat, isFunction, isInt, isKeyOf, isNonNullish, isNullish, isNumber, isObject, isPrimitive, isPromise, isString, isSymbol, iterate, keys, last, list, listify, lowerize, map, mapEntries, mapKeys, mapValues, max, memo, merge, min, objectify, omit, parallel, partial, partob, pascal, pick, proxied, random, range, reduce, replace, replaceOrAppend, retry, select, series, set, shake, shift, shuffle, sift, sleep, snake, sort, sum, template, throttle, title, toFloat, toInt, toggle, trim, tryit as try, tryit, uid, unique, upperize, zip, zipToObject };

cdn/radash.js

@@ -94,6 +94,9 @@ var radash = (function (exports) {
   const isNonNullish = (value) => {
     return value !== null && value !== void 0;
   };
+  const isKeyOf = (value, obj) => {
+    return value in obj;
+  };
 
   const group = (array, getGroupId) => {
     return array.reduce((acc, item) => {
@@ -981,6 +984,7 @@ var radash = (function (exports) {
   exports.isFloat = isFloat;
   exports.isFunction = isFunction;
   exports.isInt = isInt;
+  exports.isKeyOf = isKeyOf;
   exports.isNonNullish = isNonNullish;
   exports.isNullish = isNullish;
   exports.isNumber = isNumber;

docs/typed/is-key-of.mdx

@@ -0,0 +1,21 @@
+---
+title: isKeyOf
+description: 'Checks if the given value is a key of the given object. It is useful for narrowing down the type of a value.'
+group: Typed
+---
+
+## Basic usage
+
+Pass the object and the value to check. It will return a boolean indicating if the value is a key of the object.
+
+```ts
+import { isKeyOf } from 'radash'
+
+const obj = {
+  a: 1,
+  b: 2,
+  c: 3,
+}
+isKeyOf(obj, 'a') // true
+isKeyOf(obj, 'd') // false
+```

src/index.ts

@@ -93,6 +93,7 @@ export {
   isFloat,
   isFunction,
   isInt,
+  isKeyOf,
   isNonNullish,
   isNullish,
   isNumber,

src/tests/typed.test.ts

@@ -575,4 +575,17 @@ describe('typed module', () => {
       assert.isTrue(_.isNonNullish(new Date()))
     })
   })
+
+  describe('isKeyOf function', () => {
+    test('returns true for keys of the object', () => {
+      const obj = { name: 'ray', age: 22 }
+      assert.isTrue(_.isKeyOf('name', obj))
+      assert.isTrue(_.isKeyOf('age', obj))
+    })
+    test('returns false for keys not in the object', () => {
+      const obj = { name: 'ray', age: 22 }
+      assert.isFalse(_.isKeyOf('height', obj))
+      assert.isFalse(_.isKeyOf('weight', obj))
+    })
+  })
 })

src/typed.ts

@@ -120,3 +120,16 @@ export const isNonNullish = <TType>(
 ): value is Exclude<TType, null | undefined> => {
   return value !== null && value !== undefined
 }
+
+/**
+ * Checks if the given value is a key of the given object. It is useful for narrowing down the type of a value.
+ * @param value key to check
+ * @param obj object to check
+ * @returns true if the value is a key of the object
+ */
+export const isKeyOf = <TType extends Record<string | number | symbol, any>>(
+  value: string | number | symbol,
+  obj: TType
+): value is keyof TType => {
+  return value in obj
+}