Follow along: http://codedebugg.in
Rami Abraham;
Justin Sternberg;
PHP
echo
echo $somevar;
print_r
echo '<xmp>$somevar: '. print_r( $somevar, true ) .'</xmp>';
var_dump
echo '<div><strong>$somevar:</strong><hr>', var_dump( $somevar ), '</div>';
JS
console.log
var the_thing = 23;
if ( the_thing != 25 ) {
console.log( 'The thing is actually ' + bar );
}
PHP
debug_backtrace
echo '<xmp>backtrace: ', print_r( debug_backtrace( /*DEBUG_BACKTRACE_IGNORE_ARGS*/ ) ), '</xmp>';
get_defined_vars
echo '<xmp>defined: '. print_r( get_defined_vars(), true ) .'</xmp>';
JS
console.trace
function foo() {
function bar() {
console.trace();
}
bar();
}
foo();
err.stack
var err = new Error(); console.log( err.stack );
(logging)
PHP
memory_get_usage // or swap with microtime to get timing results
$memory_before = memory_get_usage(); do_the_thing(); echo '<xmp>'. print_r( memory_get_usage() - $memory_before . ' bytes', true ) .'</xmp>';
JS
function some_thing() {
performance.now();
console.profileStart();
do_thing();
console.profileEnd();
console.log( performance.now() );
}
PHP
die/wp_die
// or `die` works in a non-wordpress context wp_die( '<xmp>$somevar: '. print_r( $somevar, true ) .'</xmp>' );
wp_send_json_error // in an ajax context
wp_send_json_error( $somevar );
JS
setTimeout // meh
console.log( 'before pause' );
setTimeout( function() { console.log( 'after pause' ); }, 10000);
debugger // better, but best is using dev tools breakpoints.
console.log('will output');
debugger;
console.log('will not');
PHP
wp-config.php
define( 'WP_DEBUG', true ); // define( 'WP_DEBUG_DISPLAY', false ); define( 'WP_DEBUG_LOG', true );
error_log
error_log( '$somevar: '. print_r( $somevar, true ) );
$ tail -f # on the command line
tail -f PATH/TO/wp-content/debug.log
JS
log // history to an object
function log() {
log.history = log.history || [];
log.history.push( arguments );
if ( window.console && the_thing.debug ) {
window.console.log( Array.prototype.slice.call(arguments) );
}
};
PHP
JS
Start