As far as I know, Grunt is a Node Js package, so at the first time to make the Grunt commands can work, we need to install Node Js.
For instance, when run the command: grunt clean:<theme>, Gruntfile.js under Magento root folder is used. Take a look this file:
var _ = require('underscore'),
path = require('path'),
themes = require('./dev/tools/grunt/configs/themes'),
configDir = './dev/tools/grunt/configs',
taskDir = './dev/tools/grunt/tasks';
[
taskDir + '/mage-minify',
taskDir + '/deploy',
taskDir + '/black-list-generator',
taskDir + '/clean-black-list',
taskDir + '/static',
'time-grunt'
].forEach(function (task) {
require(task)(grunt);
});
We can see some configs:
1) For our theme config: themes = require('./dev/tools/grunt/configs/themes'), usually uses for grunt watch command.
2) Load config: configDir = './dev/tools/grunt/configs'.
3) Tasks: taskDir = './dev/tools/grunt/tasks'. We have some tasks: deployment, minify, etc.
Refresh themes:
/**
* Refresh themes.
*/
refresh: function () {
var tasks = [
'clean',
'exec:all'
];
_.each(themes, function(theme, name) {
tasks.push('less:' + name);
});
grunt.task.run(tasks);
},
The refresh function is the most useful function, this function defines some tasks: grunt clean:<theme>, grunt less:<theme> and exec:all
Dig into deployment task: grunt clean:<theme>
The clean config is loaded: dev/tools/grunt/configs/clean.js. And then, the deploy command is executed:
dev/tools/grunt/tasks/deploy.js
var deploy,
done = this.async();
log('Cleaning "pub/static"...');
exec('rm -rf pub/static/*');
ok('"pub/static" is empty.');
log('Deploying Magento application...');
deploy = spawn('php', ['bin/magento', 'setup:static-content:deploy']);
As we can see, Grunt -grunt clean:<theme>- will execute two commands in order:
--Delete the pub static rm -rf pub/static/
--The static content deploy command: php bin/magento setup:static-content:deploy.
Which one we will choose?
We can deploy static content in both ways, but Grunt is preferred in development mode and static content deploy command in production mode. It also makes sense because we don't need to install Node JS and do more Css style on production environment.
- $_objectManager->create() creates new instance of the object, no-matter-what
- $_objectManager->get() first tries to find shared instance (already created), if it's not found - it just creates new shared instance
If you take a look at class Magento\Framework\ObjectManager\ObjectManager, you'll notice this block:
...
/**
* Create new object instance
*
* @param string $type
* @param array $arguments
* @return mixed
*/
public function create($type, array $arguments = [])
{
$type = ltrim($type, '\\');
return $this->_factory->create($this->_config->getPreference($type), $arguments);
}
/**
* Retrieve cached object instance
*
* @param string $type
* @return mixed
*/
public function get($type)
{
$type = ltrim($type, '\\');
$type = $this->_config->getPreference($type);
if (!isset($this->_sharedInstances[$type])) {
$this->_sharedInstances[$type] = $this->_factory->create($type);
}
return $this->_sharedInstances[$type];
}
...
Best Answer
To purge out-of-date items from the cache, you can clean or flush cache types:
Cleaning a cache type deletes all items from enabled Magento cache types only. In other words, this option does not affect other processes or applications because it cleans only the cache that Magento uses.
Disabled cache types are not cleaned.
Flushing a cache type purges the cache storage, which might affect other processes applications that are using the same storage.
Flush cache types if you’ve already tried cleaning the cache and you’re still having issues that you cannot isolate.
Source: https://devdocs.magento.com/guides/v2.0/config-guide/cli/config-cli-subcommands-cache.html#config-cli-subcommands-cache-clean