src/Form.ts

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