@surface/custom-element/internal/metadata/template-metadata.js

Provides support of directives and data binding on custom elements.

export const TEMPLATE_METADATA = Symbol("custom-element:template-metadata");
export default class TemplateMetadata {
    constructor() {
        this.defaults = new Map();
        this.injections = new Map();
        this.placeholders = new Map();
    }
    static from(target) {
        if (!Reflect.has(target, TEMPLATE_METADATA)) {
            Reflect.defineProperty(target, TEMPLATE_METADATA, { configurable: false, enumerable: false, value: new TemplateMetadata() });
        }
        return Reflect.get(target, TEMPLATE_METADATA);
    }
}