Comparison Operators 
==   // equal to
===  // equal value and equal type
!=   // not equal
!==  // not equal value or not equal type
>    // greater than 
<    // less than
>=   // greater than or equal to
<=   // less than or equal to
?    // ternary operator | if true ? execute : false |

Used to compare Javascript values, returns boolean.

Operators JS
Logical Operators 
&&  // and, if both are true
||  // or, if either are true
!   // not, truthy returns false, falsy returns true

Used to determine logic between variables or values.

Operators JS
Truthy | Falsy 
false, 0, ' ', null, undefined, NaN

Above are falsy values, everything else is truthy.

Introduction JS
If...Else 
The if Statement
if (condition) {
  // executed if condition is true
}

The else Statement
if (condition) {
  // executed if condition is true
} else {
  // executed if condition is false
}

The else if Statement
if (condition1) {
  // executed if condition1 is true
} else if (condition2) {
  // executed if condition1 is false and condition2 is true
} else {
  // executed if condition1 is false and condition2 is false 
}

Nested if else Statement
if (condition1) {
  // executed if condition1 is true
} else {
  if (nestedCondition) {
    // executed if nestedCondition is true
  } else {
    // executed if nestedCondition is false
  }
}

The if...else statements executes different statements based on different conditions based on whether they are truthy or falsy.

Conditionals JS
switch 
switch(value to be matched) {
  case 'a':
      // executes if value is a
    break;
  case 'b': 
  case 'c':
      // executes if value is b or c
    break;
  default:
      // executes if no match
}

Switch statements take in a value, a changing variable maybe, to match against cases to execute code.

Conditionals JS
Ternary Operator 
condition ? true code : false code ;
condition ? true code : 2nd condition ? true code : false code ; // to chain ternaries

Used as an alternative to if else statements.

Conditionals JS
Short Circuiting 
const result = false || true; // returns the first true one with the or operator || 
const result = isEmailVerified && ‘johnDoe@gmail.com’; // Returns ‘johnDoe@gmail.com’ if isEmailVerified is true; 
const username = isEmailVerified && response || "guest"; // if false returns 'guest' otherwise returns response

Short circuiting are shorter conditional statements.

Conditionals JS