wijmo.angular2.gauge is an external TypeScript module that can be imported to your code using its ambient module name. For example:

import * as wjGauge from 'wijmo/wijmo.angular2.gauge';
 
@Component({
    directives: [wjGauge.WjLinearGauge],
    template: '<wj-linear-gauge [(value)]="amount" [isReadOnly]="false"></wj-linear-gauge>',
    selector: 'my-cmp',
})
export class MyCmp {
    amount = 0;
}