ES6 - else…if Ladder


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The else…if ladder is useful to test multiple conditions. Following is the syntax of the same.

if (boolean_expression1) { 
   //statements if the expression1 evaluates to true 
} else if (boolean_expression2) { 
   //statements if the expression2 evaluates to true 
} else { 
   //statements if both expression1 and expression2 result to false 
} 

When using if…else statements, there are a few points to keep in mind.

  • An if can have zero or one else's and it must come after any else if's.

  • An if can have zero to many else if's and they must come before the else.

  • Once an else if succeeds, none of the remaining else if's or else's will be tested.

Example

var num = 2 
if(num > 0) { 
   console.log(num+" is positive") 
} else if(num < 0) { 
   console.log(num+" is negative") 
} else { 
   console.log(num+" is neither positive nor negative") 
}

The code displays whether the value is positive, negative, or zero.

The following output is displayed on successful execution of the above code.

2 is positive

es6_decision_making.htm

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