values vs reference

last-endcode · last-endcode · commit ed45f7f4340e · 2020-10-14T10:05:35.000+07:00
diff --git a/26_values_vs_reference.js b/26_values_vs_reference.js
@@ -0,0 +1,52 @@
+// values vs reference
+// values is primitive and reference is object (array,function)
+
+const name = 'john';
+let name2 = name;
+
+console.log(`${name}`);
+console.log(`${name2}`);
+/*
+john
+john
+*/
+
+// reassign name2 : 'peter doe'
+name2 = 'peter doe';
+console.log(`${name}`);
+console.log(`${name2}`);
+
+// object or reference can't like primitive
+let value1 = {
+  name: 'edward newgate',
+};
+let value2 = value1;
+
+console.log(`${value1.name}`);
+console.log(`${value2.name}`);
+/*
+edward newgate
+edward newgate
+*/
+
+// reasign obj from value2 : 'shirohige'
+value2.name = 'shirohige';
+// and obj value1, and value2 will same cz one reference
+console.log(`${value1.name}`);
+console.log(`${value2.name}`);
+/*
+shirohige
+shirohige
+*/
+
+// but u can use copy obj
+console.log('copy obj');
+value2 = { ...value1 };
+value2.name = 'Edward NewGate Shirohige';
+
+console.log(`${value1.name}`);
+console.log(`${value2.name}`);
+/*
+shirohige
+Edward NewGate Shirohige
+*/
