addeed more snippets

Author: krishna9802

README.md

@@ -14,9 +14,17 @@ One liner clean code snippets in javascript/react with ES6 syntax
 | 1   | [Conditional statement](#conditional-statement)                                                                                                                                                                                                 |
 | 2   | [Add a key-value pair in object conditionally](#add-a-key-value-pair-in-object-conditionally)                                                                                                                                                   |
 | 3   | [Deleting a particular key from object](#deleting-a-particular-key-from-object)                                                                                                                                                                                                    |
-| 4   | [filling-array-with-dummy-values](#filling-array-with-dummy-values)                                                                                                                    |
+| 4   | [Filling array with dummy values](#filling-array-with-dummy-values)                                                                                                                    |
 
+| 5   | [Call function if it exists](#call-function-if-it-exists)                                                                                                                    |
 
+| 6   | [String to Number](#string-to-number)                                                                                                                    |
+
+| 7   | [Console related optimisation](#console-related-optimisation)                                                                                                                    |
+
+| 8   | [Overwrite by default values](#overwrite-by-default-values)                                                                                                                    |
+
+| 9   | [Conditional default value assignment for numbers](#conditional-default-value-assignment-for-numbers)                                                                                                                    |
 
 ---
 
@@ -171,6 +179,216 @@ One liner clean code snippets in javascript/react with ES6 syntax
     **[⬆ Back to Top](#table-of-contents)**
 
 
+5. ### Call function if it exists
+ 
+   **Plain javascript conditional calling**
+
+      ```javascript
+        const fun=()=>{
+          <!-- do something -->
+        }
+
+       <!-- call fun function if it exists -->
+        if(fun){
+          fun();
+        }
+      ```
+
+
+   - We will use logical AND operator to achieve same task
+   
+     ```javascript
+
+       const fun=()=>{
+          <!-- do something -->
+        }
+
+       <!-- call fun function if it exists -->
+        fun && fun();
+
+      ```
+
+      - Better way to do this
+   
+     ```javascript
+
+       const fun=()=>{
+          <!-- do something -->
+        }
+
+       fun?.();
+
+      ```
+
+    **[⬆ Back to Top](#table-of-contents)**
+
+
+
+6. ### String to Number
+
+   **Plain javascript conversion**
+
+      ```javascript
+        const num = '22';
+
+        console.log(Number(num));
+      ```
+    - Better way to do this using unary plus operator
+
+      ```javascript
+        const num = '22';
+
+        console.log(+num);
+      ```
+
+
+    **[⬆ Back to Top](#table-of-contents)**
+
+
+7. ### Console related optimization
+
+   **i. Plain javascript conditional console**
+
+      ```javascript
+        const country = 'India';
+
+        if(country){
+          console.log(`country is:${country}`);
+        }
+      ```
+    - Better way to do console using ***console.assert***
+
+      ```javascript
+        const country = 'India';
+        console.assert(country, `country is ${country}`);
+      ```
+
+
+   **ii. Named variable console**
+    
+    - Often we need to console for debugging, to keep track of variable, part and line of code, variable named console can be done by using object format.
+
+      ```javascript
+         const name = 'Krishna Kant';
+         
+         console.log(name);
+      ```
+  - Better way to do it
+
+      ```javascript
+        const name = 'Krishna Kant';
+
+        console.log({name});
+      ```
+
+
+   **iii. Grouping a set of console together**
+    
+  - Often we need to console a set of variables in a given component or function for debugging, to keep track of variable, part and line of code, we can bind them together using ***console.group***
+
+      ```javascript
+        const name = 'Krishna Kant';
+        const country = 'India';
+
+        const employee_details = {
+          organisation: 'Inventives.ai',
+          project: 'health care product',
+          team_size:'5'
+        }
+        
+        console.group('general');
+
+        console.log({name});
+        console.log({country});
+
+        console.groupEnd();
+
+
+        console.group('employe_details');
+
+        console.log({name});
+        console.log({country});
+
+        console.groupEnd();
+
+      ```
+
+
+    **[⬆ Back to Top](#table-of-contents)**
+
+
+8. ### Overwrite blocked variables by default values
+
+  - There might be instances where some variables from database could have undefined/null values and could break the code operation potentially, so we need to replace them by default values set by us manually.
+
+  **Noob assignment**
+
+      ```javascript
+          let name = 'Krishna Kant';
+          let organisation = 'Inventives.ai';
+          let project = 'health care product';
+          let team_size = '5';
+
+        function print(name, organisation, project, team_size){
+          const employee_name = name || 'Krishna';
+          const employee_organisation = organisation || 'Inventives';
+          const project = project || 'health care startup project';
+        }
+        
+      ```
+  - Better way to achieve this task using default parameters, what it does is if the value is not null or undefined, it will be assigned to the new variable otherwise new variable value assignment will pick up default values.
+
+     ```javascript
+          let name = 'Krishna Kant';
+          let organisation = 'Inventives.ai';
+          let project = 'health care product';
+          let team_size = '5';
+
+        function redefine(name ='Krishna', organisation = 'Inventives', project = 'health care startup project', team_size = 'five'){
+          const employee_name = name;
+          const employee_organisation;
+          const project = project;
+        }
+        
+      ```
+
+
+9. ### Conditional default value assignment for numbers
+
+   - Using *** || *** operator with number data types might be problematic while logical default value assignment if some variables have value 0 because 0 is read as falsey value by logical operators, 
+
+  **Plain logical assignment by || operator**
+
+      ```javascript
+          const age = 0;
+          const pending_tasks =0;
+          const team_size = 5;
+
+          const age_copy = age || 1;    <! --results 1 -->
+          const pending_tasks_copy = pending_tasks || 1; <! --results 1 -->
+          const team_size_copy = team_size || 2; <! --results 5 -->
+
+        
+      ```
+  - Better way to achieve this task using default parameters, what it does is if the value is not null or undefined, it will be assigned to the new variable otherwise new variable value assignment will pick up default values.
+
+      ```javascript
+          const age = 0;
+          const pending_tasks =0;
+          const team_size = 5;
+
+          const age_copy = age ? 1;    <! --results 0 -->
+          const pending_tasks_copy = pending_tasks || 1; <! --results 0 -->
+          const team_size_copy = team_size || 2; <! --results 5 -->
+
+        
+      ```
+
+    **[⬆ Back to Top](#table-of-contents)**
+
+
+- More code snippets are being added
+