Wrap a function in a try/catch block.
var wrap = require( '@stdlib/utils/try-function' );
Wraps a function in a try/catch block.
function fcn() {
throw new Error( 'beep boop' );
}
var f = wrap( fcn );
var out = f();
if ( out instanceof Error ) {
console.error( out.message );
// => 'beep boop'
}
The returned function has the same signature as the wrapped function.
function fcn( a, b, c, d ) {
var sum = a + b + c + d;
if ( sum < 10 ) {
throw new Error( 'invalid arguments. Arguments must sum to a number greater than or equal to 10.' );
}
return sum;
}
var f = wrap( fcn );
var out = f( 5, 6, 7, 8 );
// returns 26
out = f( 1, 2, 3, 1 );
// returns <Error>
If provided an asynchronous function, the returned function only traps errors which occur during the current event loop tick.
function fcn( a, b, clbk ) {
if ( !a ) {
throw new Error( 'invalid argument.' );
}
setTimeout( onTimeout, 0 );
function onTimeout() {
if ( !b ) {
throw new Error( 'invalid argument.' );
}
clbk();
}
}
function done() {
console.log( 'beep' );
}
var f = wrap( fcn );
var out = f( null, 5, done );
// returns <Error>
out = f( true, null, done );
// returns undefined
- Isolating try/catch blocks as separate wrapped functions prevents a parent scope from permanently entering optimization hell.
- If a function throws a literal, the literal is serialized as a string and returned as an Error object.
var wrap = require( '@stdlib/utils/try-function' );
function beep( str ) {
if ( typeof str !== 'string' ) {
throw new TypeError( 'invalid argument. Must provide a string. Value: `' + str + '`.' );
}
return 'beep ' + str;
}
function boop( str, clbk ) {
if ( typeof str !== 'string' ) {
throw new TypeError( 'invalid argument. Must provide a string. Value: `' + str + '`.' );
}
setTimeout( done, 1000 );
function done() {
if ( str !== 'beep' ) {
throw new Error( 'invalid argument. String must equal `beep`. Value: `' + str + '`.' );
}
clbk( str + ' boop' );
}
}
function done( str ) {
if ( str !== 'beep boop' ) {
throw new Error( 'huh?' );
}
}
// Synchronous...
var f = wrap( beep );
var out = f( 'boop' );
console.log( out );
// => 'beep boop'
out = f( null );
console.log( out.message );
// => '...'
// Asynchronous...
f = wrap( boop );
out = f( 'beep', done );
console.log( out );
// => undefined
out = f( 'foo', done );
console.log( out );
// => undefined