I have some code with a lot of if/else statements similar to this:
var name = "true";
if (name == "true") {
var hasName = 'Y';
} else if (name == "false") {
var hasName = 'N';
};
But is there a way to make these statements shorter? Something like ? "true" : "false" ...
7 Answers
Using the ternary :? operator [spec].
var hasName = (name === 'true') ? 'Y' :'N';
The ternary operator lets us write shorthand if..else statements exactly like you want.
It looks like:
(name === 'true') - our condition
? - the ternary operator itself
'Y' - the result if the condition evaluates to true
'N' - the result if the condition evaluates to false
So in short (question)?(result if true):(result is false) , as you can see - it returns the value of the expression so we can simply assign it to a variable just like in the example above.
You can use an object as a map:
var hasName = ({
"true" : "Y",
"false" : "N"
})[name];
This also scales nicely for many options
var hasName = ({
"true" : "Y",
"false" : "N",
"fileNotFound" : "O"
})[name];
(Bonus point for people getting the reference)
Note: you should use actual booleans instead of the string value "true" for your variables indicating truth values.
Try this
hasName = name ? 'Y' : 'N';
Try like
var hasName = 'N';
if (name == "true") {
hasName = 'Y';
}
Or even try with ternary operator like
var hasName = (name == "true") ? "Y" : "N" ;
Even simply you can try like
var hasName = (name) ? "Y" : "N" ;
Since name has either Yes or No but iam not sure with it.
?: Operator
If you want to shorten If/Else you can use ?: operator as:
condition ? action-on-true : action-on-false(else)
For instance:
let gender = isMale ? 'Male' : 'Female';
In this case else part is mandatory.
&& Operator
In another case, if you have only if condition you can use && operator as:
condition && action;
For instance:
!this.settings && (this.settings = new TableSettings());
FYI: You have to try to avoid using if-else or at least decrease using it and try to replace it with Polymorphism or Inheritance. Go for being Anti-If guy.
Most answers here will work fine if you have just two conditions in your if-else. For more which is I guess what you want, you'll be using arrays.
Every names corresponding element in names array you'll have an element in the hasNames array with the exact same index. Then it's a matter of these four lines.
names = "true";
var names = ["true","false","1","2"];
var hasNames = ["Y","N","true","false"];
var intIndex = names.indexOf(name);
hasName = hasNames[intIndex ];
This method could also be implemented using Objects and properties as illustrated by Benjamin.
Try this method;
Shorthand method:
let variable1 = '';
let variable2 = variable1 || 'new'
console.log(variable2); // newLonghand method:
let variable1 = 'ya';
let varibale2;
if (variable1 !== null || variable1 !== undefined || variable1 !== '')
variable2 = variable1;
console.log(variable2); // ya
