Ext JS 5中getNameByAlias方法移除后，如何通过别名动态匹配实现类？

Great question! When upgrading from Ext JS 4 to 5, the Ext.ClassManager.getNameByAlias method was removed, but there's a clean, efficient replacement that fits your dynamic alias-to-class mapping use case perfectly.

The Replacement: Ext.ClassManager.getByAlias() #

In Ext JS 5 and later, Ext.ClassManager.getByAlias() is the go-to method for resolving aliases to their corresponding class references. Unlike the old getNameByAlias which returned a class name string, this method directly returns the class constructor—making it more flexible for instantiation or further class operations.

Example Code #

Let's adapt your scenario where you have a class defined like this:

Ext.define('classNameIneed', {
    extend: 'SomeBaseClass',
    alias: 'aliasIhave',
    // ... other configs
});

Getting the Class Reference

To resolve your dynamic alias to the class:

// Retrieve the class using its alias
var targetClass = Ext.ClassManager.getByAlias('aliasIhave');

Getting the Class Name String (If Needed)

If you specifically need the class name string (like the old method returned), you can access the class's $className property:

var className = targetClass.$className;
// className will be 'classNameIneed'

Safe Lookup (Avoid Errors for Missing Aliases)

By default, getByAlias throws an error if the alias doesn't exist. If you want to handle missing aliases gracefully, pass false as the second strict parameter to get null instead:

var targetClass = Ext.ClassManager.getByAlias('aliasIhave', false);

if (targetClass) {
    // Proceed with class operations (e.g., create an instance)
    var instance = Ext.create(targetClass, {
        // Your config options
    });
} else {
    // Handle the case where the alias isn't registered
    console.warn('Alias not found: aliasIhave');
}

Key Notes #

• Using the direct class reference (instead of the name string) with Ext.create() is more performant, as it skips the extra step of resolving the class name again.
• This method works seamlessly with dynamically loaded classes too, as long as the alias has been registered with Ext JS's class system.

内容的提问来源于stack exchange，提问作者João