I was wondering if there is a way in javascript to have logic similar to the coalesce statement in sql which will return data in a specified order like this:
Select top 1 Coalesce(ColA, ColB, "No Data Found") from TableA;
is there an elegant way to deal with null values in Javascript, the same way that sql returns results in the above statement?
i know i could technically have a switch statement, but this would require some possibly unnecessary code
Thank you.
You can use an OR.
var someVar = null || value;
var otherVar = null || variableThatEvaluatesToNull || functionThatEvaluatesToNull() || value;
The problem with || are values like 0, which may be desired. You could write your own javascript function to simulate COALESCE.
function Coalesce() {
var args = Coalesce.arguments;
for (var i = 0; i < args.length; ++i) {
if (null !== args[i])
return args[i];
}
return null; // No non-null values found, return null
}
Which you could then call as expected:
var myNonNullValue = Coalesce(null, objectA, objectB, "defaultValue");
You can use "falsy" values and the || operator (logical OR):
var foo = bar || baz;
Above would assign the value of bar to foo if bar evaluates to a "truthy" value and baz otherwise (e.g. if bar is undefined, null, false etc.).
Here's a link to basically the same question: Is there a "null coalescing" operator in JavaScript?
That's call null coalescing. In C#, there's a null coalesce operator "??" and that's what the original asker of the linked question was referring to.
