I have an object that looks something like this:
const CONVERT = {
a: 1,
b: 2,
c: 100,
};
and I'm using it like so:
let x = 'a';
// some logic that may change x
const value = CONVERT[x];
Say I know that when x = 'c' this is an error condition. I would like to console.error( 'value clamped at the limit of 100' ) when x = 'c'.
Is there an elegant way to do this inside the CONVERT object assignment? I was hoping I could do something like this:
const CONVERT = {
a: 1,
b: 2,
c: ( ()=> { console.error( 'value clamped at the limit of 100' ); return 100; )(),
};
...but that doesn't console.error the message when CONVERT['c'] is called, Instead it does so immediately when the CONVERT object is instantiated.
The only alternative I can think of is:
let x = 'a';
// some logic that may change x
const value = CONVERT[x];
if( value === 100 ) {
console.error( 'value clamped at the limit of 100' );
}
but that means that no matter where I use CONVERT, I now need to do this extra if-check so that I can console.error the desired message. I'd like to avoid having to do this if-check completely if I know that x is not equal to 'c'.
My other choice is to get rid of the CONVERT object and instead hard code an if-else or switch like this:
let value;
if( x === 'a' ) {
value = 1;
} else if( x === 'b' ) {
value = 2;
} else if( x === 'c' ) {
value = 100;
console.error( 'value clamped at the limit of ', value );
}
This too, I'm hoping I can bypass with the use of a lookup-object instead.
You seem like you might be after a getter, which is a function which can be executed on property access. The value you return from the getter is the value which CONVERT['c'] is evaluated to:
const CONVERT = {
a: 1,
b: 2,
get c() {
console.error( 'value clamped at the limit of 100' );
return 100;
}
};
let x = 'a';
x = 'c'; // some logic that may change x
const value = CONVERT[x];
console.log(value);