If a predicate function returns a truthy value, return `x`; otherwise, return `y`.
APACHE-2.0 License
If a predicate function returns a truthy value, return
x
; otherwise, returny
.
npm install @stdlib/utils-async-if-else
Alternatively,
script
tag without installation and bundlers, use the ES Module available on the esm
branch (see README).deno
branch (see README for usage intructions).umd
branch (see README).The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
var ifelseAsync = require( '@stdlib/utils-async-if-else' );
If a predicate
function returns a truthy value, returns x
; otherwise, returns y
.
var randu = require( '@stdlib/random-base-randu' );
function predicate( clbk ) {
setTimeout( onTimeout, 0 );
function onTimeout() {
clbk( null, randu() > 0.5 );
}
}
function done( error, result ) {
if ( error ) {
throw error;
}
console.log( result );
}
ifelseAsync( predicate, 1.0, -1.0, done );
The predicate
function is provided a single argument:
clbk
: callback to invoke upon predicate
function completionThe callback accepts two arguments:
error
: error objectbool
: condition used to determine whether to return x
or y
The done
callback is invoked upon function completion and is provided at most two arguments:
error
: error objectresult
: either x
or y
done
callback in a function which either executes at the end of the current stack (e.g., nextTick
) or during a subsequent turn of the event loop (e.g., setImmediate
, setTimeout
).var randu = require( '@stdlib/random-base-randu' );
var ifelseAsync = require( '@stdlib/utils-async-if-else' );
var i;
function next() {
ifelseAsync( predicate, 'BOOP', 'beep', done );
}
function predicate( clbk ) {
setTimeout( onTimeout, 0 );
function onTimeout() {
clbk( null, randu() > 0.9 );
}
}
function done( error, result ) {
if ( error ) {
throw error;
}
i += 1;
console.log( result );
if ( i < 100 ) {
return next();
}
}
i = 0;
next();
@stdlib/utils-async/if-then
: if a predicate function returns a truthy value, invoke x
; otherwise, invoke y
.
@stdlib/utils-if-else
: if a condition is truthy, return x
; otherwise, return y
.
This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.
See LICENSE.
Copyright © 2016-2024. The Stdlib Authors.