src/core/Form.ts

   1 // Copyright 2020 Blue Static <https://www.bluestatic.org>
   2 // This program is free software licensed under the GNU General Public License,
   3 // version 3.0. The full text of the license can be found in LICENSE.txt.
   4 // SPDX-License-Identifier: GPL-3.0-only
   5
   6 import Person from './Person';
   7 import TaxReturn from './TaxReturn';
   8 import Trace from './Trace';
   9 import { Line } from './Line';
  10 import { InconsistencyError, NotFoundError } from './Errors';
  11
  12 export default abstract class Form<L extends { [key: string]: Line<any> },
  13                                    I = unknown> {
  14   abstract readonly name: string;
  15
  16   protected abstract readonly _lines: L;
  17
  18   readonly supportsMultipleCopies: boolean = false;
  19
  20   private readonly _input?: I;
  21
  22   // Avoid using this; prefer the getLine() helpers declared below. This
  23   // is only exposed for propagating line type information.
  24   get lines(): L { return this._lines; }
  25
  26   constructor(input?: I) {
  27     this._input = input;
  28   }
  29
  30   init() {
  31     for (const id in this._lines) {
  32       let l = this._lines[id];
  33       l._id = id;
  34       l.form = this;
  35     }
  36   }
  37
  38   person(): Person | undefined {
  39     return undefined;
  40   }
  41
  42   getLine<K extends keyof L>(id: K): L[K] {
  43     if (!(id in this._lines))
  44       throw new NotFoundError(`Form ${this.name} does not have line ${id}`);
  45     return this._lines[id];
  46   }
  47
  48   getValue<K extends keyof L>(tr: TaxReturn, id: K): ReturnType<L[K]['value']> {
  49     const line: L[K] = this.getLine(id);
  50     return line.value(tr);
  51   }
  52
  53   getInput<K extends keyof I>(name: K): I[K] {
  54     if (!(name in this._input)) {
  55       throw new NotFoundError(`No input with key ${name} on form ${this.name}`);
  56     }
  57     Trace.add(`${this.name} input: ${name}`);
  58     return this._input[name];
  59   }
  60
  61   hasInput<K extends keyof I>(name: K): boolean {
  62     return this._input !== undefined && name in this._input;
  63   }
  64 };
  65
  66 export type FormClass<T extends Form<any>> = new (...args: any[]) => T;
  67
  68 export function isFormT<T extends Form<any>>(form: Form<any>,
  69                                              formClass: FormClass<T>):
  70                                                 form is T {
  71   return form.constructor === formClass;
  72 }