JavaScript - IF Condition - Part 4

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Miscellaneous Truthy and Falsey expressions

In this blog, I will discuss various conditional expressions that I have not discussed in the first three parts.

Case 1: The function returning an undefined value is evaluated as Falsey.

function Fx() {
    console.log("This is Fx");
}
if (Fx()) 
    console.log("Call is - Truthy");
else
    console.log("Call is - Falsey");

Case 2: The function returns an integer. The conditional expression is evaluated as Truthy.

function Fx() {
    return 100;  // return - fractional number - result : Truthy
}
if (Fx()) 
    console.log("Fx() - Truthy");

Case 3: The function returns a null value. The conditional expression is evaluated as Falsey.

function Fx() {
    return null
}
if (Fx()) 
    console.log("Fx() - Truthy");
else
    console.log("Fx() - Falsey");

Case 4: When a conditional expression is an array object. It is evaluated as Truthy.

let arr = [12,2,34]
if(arr)
    console.log("array - Truthy");

Case 5: When a conditional expression is an object. It is evaluated as Truthy.

let myobj = {
    a:10,
    b:"Date"
 };

if(myobj) 
    console.log("object - Truthy");

Case 6: When a conditional expression is a function object. It is evaluated as Truthy.

function Fx() {
    console.log("This is a Fx function");
}

if (Fx) // Not calling the function
    console.log("Function object - Truthy")

Complete Code Listing

/*
Author: Mahavir DS Rathore
Objective: Miscellaneous Conditional Expressions
*/
function Fx() {
    return 10;
}

function Fx2() {
    return 20.1;
}

function Fx3() {
    return null;
}

function Fx4() {
    console.log("This is Fx");
}

if (Fx())
  console.log("Fx() - true");

if(Fx2())   
    console.log("Fx2() - true");

if(Fx3())    
    console.log("Fx3() - true");
else 
    console.log("Fx3() - false");  // false

if (Fx4()) 
    console.log("Call is - Truthy");
else
    console.log("Call is - Falsey"); // false


if (Fx)
    console.log("Fx - true");

var arr = [1,2,3];

if (arr)
  console.log("arr - true");

var obj = {
    a : 12,
    b : "Ram"
};

if (obj) 
    console.log("obj - true");

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