Best Way for Conditional Variable Assignment

Question

Which is the better way for conditional variable assignment?

1st method

 if (true) {
   var myVariable = \'True\';
 } else {
   var myVariable = \'False\         


        

Answer 1

Another cool thing is that you can do multiple assignment based on a conditional:

let [long_str, short_str] = a.length > b.length ? [a, b] : [b, a]

Answer 2

There are two methods I know of that you can declare a variable's value by conditions.

Method 1: If the condition evaluates to true, the value on the left side of the column would be assigned to the variable. If the condition evaluates to false the condition on the right will be assigned to the variable. You can also nest many conditions into one statement.

var a = (true)? "true" : "false";

Nesting example of method 1: Change variable A value to 0, 1, 2 and a negative value to see how the statement would produce the result.

var a = 1;
var b = a > 0? (a === 1? "A is 1" : "A is not 1") : (a === 0? "A is zero" : "A is negative");

Method 2: In this method, if the value of the left of the || is equal to zero, false, null, undefined, or an empty string, then the value on the right will be assigned to the variable. If the value on the left of the || does not equal to zero, false, null undefined, or an empty string, then the value on the left will be assigned to the variable.

Although the value on the left can be an undefined value for JS to evaluate the condition but the variable has to be declared otherwise an exception will be produced.

var a = 0;
var b = a || "Another value";

Answer 3

Maybe you simply need && operator to check if boolean is true, if it is, assing "myVariable" to true.

var myVariable = 'False';
true && myVariable = 'True';

Answer 4

The first solution uses only one assignment instead of 1,5 by average in the second code snippet. On the other hand the first code snippet is less readable as people not familiar with JavaScript might not realize that the scope of a variable is not block oriented by function oriented - on other languages with C-like syntax myVariable would not be accessible outside if and else blocks.

In other words both solutions have disadvantages. What about ternary operator:

var myVariable = condition? 'True' : 'False';

or if you don't care about the camel-case (although I understand this is just an example, not a real code);

var myVariable = (!!condition).toString();

Answer 5

let value = function(condition){
    if(condition) {
        return "true";
    } else {
        return "false";
    }
}

console.log(value(true));

Answer 6

I would prefer 2nd option too, no technical reason but for the sake of easy to read code, readability is very important in code.

If you see the second option, from processing point of view only one check will ever be executed, saved some very minute processing time, so there is only one check in second case.