Why empty array is true in javascript if condition

Following values are always false

false
0
"" (empty string)
null
undefined
NaN

Following values are true
"0" - zero within string
"false"
empty arrays
empty functions
empty objects

function test(){
    let validations = {"wrongParams":[], "missingParams":[]};
	if(validations.missingParams) {
		console.log('hi');
	}
	else{
		console.log("hello");
	}
}

Above program prints "hi" because it is evaluating empty array.

Why?

if (arr) called on object (Array is instance of object in Javascript) will check if the object is present and returns true/false.

When you call if(arr === false) you compare values of this object and the primitive false value. Internally arr.toString gets called which returns an empty string "". Emptry string is one of falsy values in Javascript.