trapify

Create proxy objects with custom property access behavior.

Interface

this.trapify(object)

Parameters

• object - The object to wrap, optionally containing special trap methods

Returns

• A proxy object with custom get/set behavior

Description

The trapify service creates enhanced proxy objects that intercept property access and modification. It supports special methods prefixed with __ that define custom behaviors for missing properties, making it useful for dynamic property generation, service containers, and metaprogramming patterns.

Special Methods

• __getMissing(target, name) - Called when accessing a non-existent property
• __setMissing(target, name, value) - Called when setting a property without a setter

Standard JavaScript proxy traps can also be implemented with __ prefix: __get, __set, __has, __deleteProperty, __ownKeys, etc.

Examples

Dynamic Property Handler

const config = this.trapify({
    host: 'localhost',
    __getMissing(target, name) {
        return `Unknown config: ${name}`;
    }
});

config.host;      // 'localhost'
config.anything;  // 'Unknown config: anything'

CSS Class Generator

const classes = this.trapify({
    __getMissing(target, name) {
        return `component-${this.inflector.dasherize(name)}`;
    }
});

classes.submitButton;  // 'component-submit-button'
classes.errorMessage;  // 'component-error-message'

Dynamic Service Container

const services = this.trapify({
    __getMissing(target, serviceName) {
        return ServiceFactory.create(serviceName);
    }
});

const database = services.database;  // Creates database service on demand

Custom Setter Logic

const validated = this.trapify({
    _data: {},
    __setMissing(target, name, value) {
        if (typeof value === 'string' && value.length > 100) {
            throw new Error(`Value for ${name} too long`);
        }
        target._data[name] = value;
        return true;
    },
    __getMissing(target, name) {
        return target._data[name];
    }
});

validated.title = 'Hello';  // Works
validated.title;            // 'Hello'

Notes

• Existing properties and getters take precedence over __getMissing
• Trap methods receive the trapified this context
• Used internally for database table access and CSS class generation