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If a predicate function returns a truthy value, return
x; otherwise, returny.
import ifelseAsync from 'https://cdn.jsdelivr.net/gh/stdlib-js/utils-async-if-else@esm/index.mjs';If a predicate function returns a truthy value, returns x; otherwise, returns y.
import randu from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-base-randu@esm/index.mjs';
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 uponpredicatefunction completion
The callback accepts two arguments:
error: error objectbool: condition used to determine whether to returnxory
The done callback is invoked upon function completion and is provided at most two arguments:
error: error objectresult: eitherxory
- Execution is not guaranteed to be asynchronous. To guarantee asynchrony, wrap the
donecallback 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).
<!DOCTYPE html>
<html lang="en">
<body>
<script type="module">
import randu from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-base-randu@esm/index.mjs';
import ifelseAsync from 'https://cdn.jsdelivr.net/gh/stdlib-js/utils-async-if-else@esm/index.mjs';
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();
</script>
</body>
</html>@stdlib/utils-async/if-then: if a predicate function returns a truthy value, invokex; otherwise, invokey.@stdlib/utils-if-else: if a condition is truthy, returnx; otherwise, returny.
This package is part of stdlib, a standard library 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.
