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Twittercompute
A derived value from other computes and observable maps.
compute([newVal])
Gets the compute's value if no arguments are provided, otherwise calls the compute's setter with the value passed as the first argument.
Parameters
- newVal
{*}:If the compute is called with an argument, the first argument is used to set the compute to a new value. This may trigger a
"change"event that can be listened for with [can-computed.bind].If the compute is called without any arguments (
compute()), it simply returns the current value.
Returns
{*}:
The current value of the compute.
Use
A compute instance is created with can-compute and used as an observable value. Computes are useful to provide a value representative of multiple other observables:
const person = new Person( {
first: "Matthew",
last: "Phillips"
} );
const fullName = compute( function() {
return person.first + " " + person.last;
} );
console.log( fullName() ); // -> "Matthew Phillips".
Calling the compute with a value will cause it to run as a setter function:
const count = compute( 0 );
console.log( count() ); // -> 0
count( 5 );
console.log( count() ); // -> 5
This depends on how the getterSetter is defined, and can adjust how it handles setters:
const plusOne = compute( function( val ) {
if ( val ) {
return val + 1;
} else {
return 1;
}
} );
console.log( plusOne() ); // -> 1
plusOne( 5 );
console.log( plusOne() ); // -> 6