diff --git a/README.md b/README.md index 4996266d6..365063973 100644 --- a/README.md +++ b/README.md @@ -272,6 +272,7 @@ average(1, 2, 3);
View contents +* [`deepClone`](#deepclone) * [`defaults`](#defaults) * [`equals`](#equals-) * [`findKey`](#findkey) @@ -4191,6 +4192,37 @@ UUIDGeneratorNode(); // '79c7c136-60ee-40a2-beb2-856f1feabefc' --- ## 🗃️ Object +### deepClone + +Creates a deep clone of an object. + +Use recursion. +Use `Object.assign()` and an empty object (`{}`) to create a shallow clone of the original. +Use `Object.keys()` and `Array.forEach()` to determine which key-value pairs need to be deep cloned. + +```js +const deepClone = obj => { + let clone = Object.assign({}, obj); + Object.keys(clone).forEach( + key => (clone[key] = typeof obj[key] === 'object' ? deepClone(obj[key]) : obj[key]) + ); + return clone; +}; +``` + +
+Examples + +```js +const a = { foo: 'bar', obj: { a: 1, b: 2 } }; +const b = deepClone(a); // a !== b, a.obj !== b.obj +``` + +
+ +
[⬆ Back to top](#table-of-contents) + + ### defaults Assigns default values for all properties in an object that are `undefined`. diff --git a/docs/index.html b/docs/index.html index ecf29f79d..2e0a86db1 100644 --- a/docs/index.html +++ b/docs/index.html @@ -50,7 +50,7 @@ scrollToTop(); } }, false); - }

logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.

 

Adapter

call

Given a key and a set of arguments, call them when given a context. Primarily useful in composition.

Use a closure to call a stored key with stored arguments.

const call = (key, ...args) => context => context[key](...args);
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Adapter
call
Given a key and a set of arguments, call them when given a context. Primarily useful in composition.
Use a closure to call a stored key with stored arguments.
const call = (key, ...args) => context => context[key](...args);
 
Promise.resolve([1, 2, 3])
   .then(call('map', x => 2 * x))
   .then(console.log); //[ 2, 4, 6 ]
@@ -936,7 +936,16 @@ console.log<
     (c ^ (crypto.randomBytes(1)[0] & (15 >> (c / 4)))).toString(16)
   );
 
UUIDGeneratorNode(); // '79c7c136-60ee-40a2-beb2-856f1feabefc'
-
Object
defaults
Assigns default values for all properties in an object that are undefined.
Use Object.assign() to create a new empty object and copy the original one to maintain key order, use Array.reverse() and the spread operator ... to combine the default values from left to right, finally use obj again to overwrite properties that originally had a value.
const defaults = (obj, ...defs) => Object.assign({}, obj, ...defs.reverse(), obj);
+
Object
deepClone
Creates a deep clone of an object.
Use recursion. Use Object.assign() and an empty object ({}) to create a shallow clone of the original. Use Object.keys() and Array.forEach() to determine which key-value pairs need to be deep cloned.
const deepClone = obj => {
+  let clone = Object.assign({}, obj);
+  Object.keys(clone).forEach(
+    key => (clone[key] = typeof obj[key] === 'object' ? deepClone(obj[key]) : obj[key])
+  );
+  return clone;
+};
+
const a = { foo: 'bar', obj: { a: 1, b: 2 } };
+const b = deepClone(a); // a !== b, a.obj !== b.obj
+
defaults
Assigns default values for all properties in an object that are undefined.
Use Object.assign() to create a new empty object and copy the original one to maintain key order, use Array.reverse() and the spread operator ... to combine the default values from left to right, finally use obj again to overwrite properties that originally had a value.
const defaults = (obj, ...defs) => Object.assign({}, obj, ...defs.reverse(), obj);
 
defaults({ a: 1 }, { b: 2 }, { b: 6 }, { a: 3 }); // { a: 1, b: 2 }
 
equalsadvanced
Performs a deep comparison between two values to determine if they are equivalent.
Check if the two values are identical, if they are both Date objects with the same time, using Date.getTime() or if they are both non-object values with an equivalent value (strict comparison). Check if only one value is null or undefined or if their prototypes differ. If none of the above conditions are met, use Object.keys() to check if both values have the same number of keys, then use Array.every() to check if every key in the first value exists in the second one and if they are equivalent by calling this method recursively.
const equals = (a, b) => {
   if (a === b) return true;
diff --git a/snippets/deepClone.md b/snippets/deepClone.md
index 360505318..fe2af84eb 100644
--- a/snippets/deepClone.md
+++ b/snippets/deepClone.md
@@ -10,10 +10,7 @@ Use `Object.keys()` and `Array.forEach()` to determine which key-value pairs nee
 const deepClone = obj => {
   let clone = Object.assign({}, obj);
   Object.keys(clone).forEach(
-    key =>
-      (clone[key] = typeof obj[key] === 'object'
-        ? deepClone(obj[key])
-        : obj[key])
+    key => (clone[key] = typeof obj[key] === 'object' ? deepClone(obj[key]) : obj[key])
   );
   return clone;
 };