Improve the type coverage of clone function (#62)

* Improve the type coverage of clone function

cdn/.version

@@ -1 +1 @@
-9.1.0
+9.2.0

cdn/radash.esm.js

@@ -434,6 +434,9 @@ const isArray = (value) => {
 const isObject = (value) => {
   return !!value && value.constructor === Object;
 };
+const isPrimitive = (value) => {
+  return value === void 0 || value === null || typeof value !== "object" && typeof value !== "function";
+};
 const isFunction = (value) => {
   return !!(value && value.constructor && value.call && value.apply);
 };
@@ -560,13 +563,17 @@ const invert = (obj) => {
 const lowerize = (obj) => mapKeys(obj, (k) => k.toLowerCase());
 const upperize = (obj) => mapKeys(obj, (k) => k.toUpperCase());
 const clone = (obj) => {
-  return Object.getOwnPropertyNames(obj).reduce(
-    (acc, name) => ({
-      ...acc,
-      [name]: obj[name]
-    }),
-    {}
-  );
+  if (isPrimitive(obj)) {
+    return obj;
+  }
+  if (typeof obj === "function") {
+    return obj.bind({});
+  }
+  const newObj = new obj.constructor();
+  Object.getOwnPropertyNames(obj).forEach((prop) => {
+    newObj[prop] = obj[prop];
+  });
+  return newObj;
 };
 const listify = (obj, toItem) => {
   if (!obj)
@@ -754,4 +761,4 @@ const template = (str, data, regex = /\{\{(.+?)\}\}/g) => {
   }, str);
 };
 
-export { alphabetical, boil, camel as camal, camel, capitalize, chain, clone, cluster, compose, counting, dash, debounce, defer, diff, draw, first, flat, fork, get, group, intersects, invert, isArray, isDate, isEmpty, isEqual, isFloat, isFunction, isInt, isNumber, isObject, isString, isSymbol, iterate, 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, shake, shift, shuffle, sift, sleep, snake, sort, sum, template, throttle, toFloat, toInt, toggle, tryit as try, tryit, uid, unique, upperize, zip };
+export { alphabetical, boil, camel as camal, camel, capitalize, chain, clone, cluster, compose, counting, dash, debounce, defer, diff, draw, first, flat, fork, get, group, intersects, invert, isArray, isDate, isEmpty, isEqual, isFloat, isFunction, isInt, isNumber, isObject, isPrimitive, isString, isSymbol, iterate, 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, shake, shift, shuffle, sift, sleep, snake, sort, sum, template, throttle, toFloat, toInt, toggle, tryit as try, tryit, uid, unique, upperize, zip };

cdn/radash.js

@@ -437,6 +437,9 @@ var radash = (function (exports) {
   const isObject = (value) => {
     return !!value && value.constructor === Object;
   };
+  const isPrimitive = (value) => {
+    return value === void 0 || value === null || typeof value !== "object" && typeof value !== "function";
+  };
   const isFunction = (value) => {
     return !!(value && value.constructor && value.call && value.apply);
   };
@@ -563,13 +566,17 @@ var radash = (function (exports) {
   const lowerize = (obj) => mapKeys(obj, (k) => k.toLowerCase());
   const upperize = (obj) => mapKeys(obj, (k) => k.toUpperCase());
   const clone = (obj) => {
-    return Object.getOwnPropertyNames(obj).reduce(
-      (acc, name) => ({
-        ...acc,
-        [name]: obj[name]
-      }),
-      {}
-    );
+    if (isPrimitive(obj)) {
+      return obj;
+    }
+    if (typeof obj === "function") {
+      return obj.bind({});
+    }
+    const newObj = new obj.constructor();
+    Object.getOwnPropertyNames(obj).forEach((prop) => {
+      newObj[prop] = obj[prop];
+    });
+    return newObj;
   };
   const listify = (obj, toItem) => {
     if (!obj)
@@ -788,6 +795,7 @@ var radash = (function (exports) {
   exports.isInt = isInt;
   exports.isNumber = isNumber;
   exports.isObject = isObject;
+  exports.isPrimitive = isPrimitive;
   exports.isString = isString;
   exports.isSymbol = isSymbol;
   exports.iterate = iterate;

package.json

@@ -1,6 +1,6 @@
 {
   "name": "radash",
-  "version": "9.1.0",
+  "version": "9.2.0",
   "description": "Functional utility library - modern, simple, typed, powerful",
   "main": "dist/cjs/index.cjs",
   "module": "dist/esm/index.mjs",

src/index.ts

@@ -91,6 +91,7 @@ export {
   isInt,
   isNumber,
   isObject,
+  isPrimitive,
   isString,
   isSymbol
 } from './typed'

src/object.ts

@@ -1,4 +1,4 @@
-import { isFunction, isObject } from './typed'
+import { isFunction, isObject, isPrimitive } from './typed'
 
 type LowercasedKeys<T extends Record<string, any>> = {
   [P in keyof T & string as Lowercase<P>]: T[P]
@@ -124,14 +124,32 @@ export const lowerize = <T extends Record<string, any>>(obj: T) =>
 export const upperize = <T extends Record<string, any>>(obj: T) =>
   mapKeys(obj, k => k.toUpperCase()) as UppercasedKeys<T>
 
-export const clone = <T extends object = object>(obj: T): T => {
-  return Object.getOwnPropertyNames(obj).reduce(
-    (acc, name) => ({
-      ...acc,
-      [name]: obj[name as keyof T]
-    }),
-    {} as T
-  )
+/**
+ * Creates a shallow copy of the given obejct/value.
+ * @param {*} obj value to clone
+ * @returns {*} shallow clone of the given value
+ */
+export const clone = <T>(obj: T): T => {
+  // Primitive values do not need cloning.
+  if (isPrimitive(obj)) {
+    return obj
+  }
+
+  // Binding a function to an empty object creates a copy function.
+  if (typeof obj === 'function') {
+    return obj.bind({})
+  }
+
+  // Access the constructor and create a new object. This method can create an array as well.
+  const newObj = new ((obj as Object).constructor as { new (): T })()
+
+  // Assign the props.
+  Object.getOwnPropertyNames(obj).forEach(prop => {
+    // Bypass type checking since the primitive cases are already checked in the beginning
+    ;(newObj as any)[prop] = (obj as any)[prop]
+  })
+
+  return newObj
 }
 
 /**

src/tests/object.test.ts

@@ -102,6 +102,50 @@ describe('object module', () => {
   })
 
   describe('clone function', () => {
+    test('copies the primitives', () => {
+      const arr = [
+        1.1,
+        'How you doin?',
+        false,
+        Symbol('key'),
+        BigInt('1'),
+        undefined,
+        null
+      ]
+      for (const elm of arr) {
+        const newElm = _.clone(elm)
+        assert.equal(elm, newElm)
+      }
+    })
+    test('copies arrays', () => {
+      const arr = [{ a: 0 }, 1, 2, 3]
+      const result = _.clone(arr)
+
+      assert.notEqual(arr, result)
+      for (const i in result) {
+        assert.equal(arr[i], result[i])
+      }
+    })
+    test('copies functions', () => {
+      const fa = () => 0
+      const fb = _.clone(fa)
+
+      assert.notEqual(fa, fb)
+      assert.equal(fa(), fb())
+    })
+    test('copies objects (class instances) without losing the class type', () => {
+      class Data {
+        val = 0
+      }
+
+      const obj = new Data()
+      obj.val = 1
+      const result = _.clone(obj)
+
+      assert.notEqual(obj, result)
+      assert.equal(obj.constructor.name, result.constructor.name)
+      assert.equal(obj.val, result.val)
+    })
     test('copies all attributes from object', () => {
       const obj = {
         x: 22,

src/tests/typed.test.ts

@@ -78,6 +78,31 @@ describe('typed module', () => {
     })
   })
 
+  describe('isPrimitive function', () => {
+    test('returns true for all the primitives', () => {
+      const arr = [
+        1.1,
+        'How you doin?',
+        false,
+        Symbol('key'),
+        BigInt('1'),
+        undefined,
+        null
+      ]
+
+      for (const elm of arr) {
+        assert.isTrue(_.isPrimitive(elm))
+      }
+    }),
+      test('returns false for non-primitives', () => {
+        const arr = [new Date(), Number, {}, Object({}), () => 0, [1, 2]]
+
+        for (const elm of arr) {
+          assert.isFalse(_.isPrimitive(elm))
+        }
+      })
+  })
+
   describe('isFunction function', () => {
     test('returns false for null', () => {
       const result = _.isFunction(null)

src/typed.ts

@@ -10,6 +10,22 @@ export const isObject = (value: any): value is object => {
   return !!value && value.constructor === Object
 }
 
+/**
+ * Checks if the given value is primitive.
+ *
+ * Primitive Types: number , string , boolean , symbol, bigint, undefined, null
+ *
+ * @param {*} value value to check
+ * @returns {boolean} result
+ */
+export const isPrimitive = (value: any): boolean => {
+  return (
+    value === undefined ||
+    value === null ||
+    (typeof value !== 'object' && typeof value !== 'function')
+  )
+}
+
 export const isFunction = (value: any): value is Function => {
   return !!(value && value.constructor && value.call && value.apply)
 }