src/core/Form.ts

   1 import Person from './Person';
   2 import TaxReturn from './TaxReturn';
   3 import { Line } from './Line';
   4 import { InconsistencyError, NotFoundError } from './Errors';
   5
   6 export default abstract class Form<L extends { [key: string]: Line<any> },
   7                                    I = unknown> {
   8   abstract readonly name: string;
   9
  10   protected abstract readonly _lines: L;
  11
  12   readonly supportsMultipleCopies: boolean = false;
  13
  14   private readonly _input?: I;
  15
  16   // Avoid using this; prefer the getLine() helpers declared below. This
  17   // is only exposed for propagating line type information.
  18   get lines(): L { return this._lines; }
  19
  20   constructor(input?: I) {
  21     this._input = input;
  22   }
  23
  24   init() {
  25     for (const id in this._lines) {
  26       let l = this._lines[id];
  27       l._id = id;
  28       l.form = this;
  29     }
  30   }
  31
  32   person(): Person | undefined {
  33     return undefined;
  34   }
  35
  36   getLine<K extends keyof L>(id: K): L[K] {
  37     if (!(id in this._lines))
  38       throw new NotFoundError(`Form ${this.name} does not have line ${id}`);
  39     return this._lines[id];
  40   }
  41
  42   getValue<K extends keyof L>(tr: TaxReturn, id: K): ReturnType<L[K]['value']> {
  43     const line: L[K] = this.getLine(id);
  44     return line.value(tr);
  45   }
  46
  47   getInput<K extends keyof I>(name: K): I[K] {
  48     if (!(name in this._input)) {
  49       throw new NotFoundError(`No input with key ${name} on form ${this.name}`);
  50     }
  51     return this._input[name];
  52   }
  53
  54   hasInput<K extends keyof I>(name: K): boolean {
  55     return this._input !== undefined && name in this._input;
  56   }
  57 };
  58
  59 export type FormClass<T extends Form<any>> = new (...args: any[]) => T;
  60
  61 export function isFormT<T extends Form<any>>(form: Form<any>,
  62                                              formClass: FormClass<T>):
  63                                                 form is T {
  64   return form.constructor === formClass;
  65 }