radio.ts

import { Injectable } from '@angular/core';
import { NgControl } from '@angular/forms';

/**
 * Inspired by https://goo.gl/Xrhoku
 */
@Injectable()
export class RadioControlRegistry {
    private _accessors: any[] = [];

    add(control: NgControl, accessor: any) {
        this._accessors.push([control, accessor]);
    }

    remove(accessor: any) {
        for (let i = this._accessors.length - 1; i >= 0; --i) {
            if (this._accessors[i][1] === accessor) {
                this._accessors.splice(i, 1);
                return;
            }
        }
    }

    select(accessor: any) {
        this._accessors.forEach(c => {
            if (this._isSameGroup(c, accessor)) {
                c[1].writeValue(accessor.value);
            }
        });
    }

    private _isSameGroup(controlPair: [any, any], accessor: any): boolean {
        if (!controlPair[0].control) {
            return false;
        }

        return controlPair[0]._parent === accessor._control._parent && controlPair[1].name === accessor.name;
    }