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 { Line } from './Line';
   9 import { InconsistencyError, NotFoundError } from './Errors';
  10
  11 export default abstract class Form<L extends { [key: string]: Line<any> },
  12                                    I = unknown> {
  13   abstract readonly name: string;
  14
  15   protected abstract readonly _lines: L;
  16
  17   readonly supportsMultipleCopies: boolean = false;
  18
  19   private readonly _input?: I;
  20
  21   // Avoid using this; prefer the getLine() helpers declared below. This
  22   // is only exposed for propagating line type information.
  23   get lines(): L { return this._lines; }
  24
  25   constructor(input?: I) {
  26     this._input = input;
  27   }
  28
  29   init() {
  30     for (const id in this._lines) {
  31       let l = this._lines[id];
  32       l._id = id;
  33       l.form = this;
  34     }
  35   }
  36
  37   person(): Person | undefined {
  38     return undefined;
  39   }
  40
  41   getLine<K extends keyof L>(id: K): L[K] {
  42     if (!(id in this._lines))
  43       throw new NotFoundError(`Form ${this.name} does not have line ${id}`);
  44     return this._lines[id];
  45   }
  46
  47   getValue<K extends keyof L>(tr: TaxReturn, id: K): ReturnType<L[K]['value']> {
  48     const line: L[K] = this.getLine(id);
  49     return line.value(tr);
  50   }
  51
  52   getInput<K extends keyof I>(name: K): I[K] {
  53     if (!(name in this._input)) {
  54       throw new NotFoundError(`No input with key ${name} on form ${this.name}`);
  55     }
  56     return this._input[name];
  57   }
  58
  59   hasInput<K extends keyof I>(name: K): boolean {
  60     return this._input !== undefined && name in this._input;
  61   }
  62 };
  63
  64 export type FormClass<T extends Form<any>> = new (...args: any[]) => T;
  65
  66 export function isFormT<T extends Form<any>>(form: Form<any>,
  67                                              formClass: FormClass<T>):
  68                                                 form is T {
  69   return form.constructor === formClass;
  70 }