@@ -927,9 +927,7 @@ inventoryTracker('apples', req, 'www.inventory-awesome.io');
927927
928928## ** Objects and Data Structures**
929929### Use getters and setters
930- JavaScript doesn't have interfaces or types so it is very hard to enforce this
931- pattern, because we don't have keywords like ` public ` and ` private ` . As it is,
932- using getters and setters to access data on objects is far better than simply
930+ Using getters and setters to access data on objects could be better than simply
933931looking for a property on an object. "Why?" you might ask. Well, here's an
934932unorganized list of reasons why:
935933
@@ -938,56 +936,51 @@ to look up and change every accessor in your codebase.
938936* Makes adding validation simple when doing a ` set ` .
939937* Encapsulates the internal representation.
940938* Easy to add logging and error handling when getting and setting.
941- * Inheriting this class, you can override default functionality.
942939* You can lazy load your object's properties, let's say getting it from a
943940server.
944941
945942
946943** Bad:**
947944``` javascript
948- class BankAccount {
949- constructor () {
950- this .balance = 1000 ;
951- }
952- }
945+ function makeBankAccount () {
946+ // ...
953947
954- const bankAccount = new BankAccount ();
948+ return {
949+ balance: 0 ,
950+ // ...
951+ };
952+ }
955953
956- // Buy shoes...
957- bankAccount .balance - =100 ;
954+ const account = makeBankAccount ();
955+ account .balance = 100 ;
958956```
959957
960958** Good:**
961959``` javascript
962- class BankAccount {
963- constructor (balance = 1000 ) {
964- this ._balance = balance;
965- }
960+ function makeBankAccount () {
961+ // this one is private
962+ let balance = 0 ;
966963
967- // It doesn't have to be prefixed with `get` or `set` to be a getter/setter
968- set balance (amount ) {
969- if (this .verifyIfAmountCanBeSetted (amount)) {
970- this ._balance = amount;
971- }
964+ // a "getter", made public via the returned object below
965+ function getBalance () {
966+ return balance;
972967 }
973968
974- get balance () {
975- return this ._balance ;
969+ // a "setter", made public via the returned object below
970+ function setBalance (amount ) {
971+ // ... validate before updating the balance
972+ balance = amount;
976973 }
977974
978- verifyIfAmountCanBeSetted ( val ) {
975+ return {
979976 // ...
980- }
977+ getBalance,
978+ setBalance,
979+ };
981980}
982981
983- const bankAccount = new BankAccount ();
984- 985- // Buy shoes...
986- bankAccount .balance -= shoesPrice;
987- 988- // Get balance
989- let balance = bankAccount .balance ;
990- 982+ const account = makeBankAccount ();
983+ account .setBalance (100 );
991984```
992985** [ ⬆ back to top] ( #table-of-contents ) **
993986
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