src/Line.ts

   1 import TaxReturn from './TaxReturn';
   2 import Form from './Form';
   3
   4 export abstract class Line<T> {
   5   private _description?: string;
   6
   7   _id: string;  // _id is set by Form.init().
   8   form: Form<any, any>;  // Set by Form.init();
   9
  10   constructor(description?: string) {
  11     this._description = description;
  12   }
  13
  14   get id(): string {
  15     return this._id;
  16   }
  17
  18   get description(): string {
  19     return this._description;
  20   }
  21
  22   abstract value(tr: TaxReturn): T;
  23 };
  24
  25 type ComputeFunc<T> = (tr: TaxReturn, l: ComputedLine<T>) => T;
  26
  27 export class ComputedLine<T> extends Line<T> {
  28   private _compute: ComputeFunc<T>;
  29
  30   constructor(compute: ComputeFunc<T>, description?: string) {
  31     super(description);
  32     this._compute = compute;
  33   }
  34
  35   value(tr: TaxReturn): T {
  36     return this._compute(tr, this);
  37   }
  38 };
  39
  40 export class ReferenceLine<T> extends Line<T> {
  41   private _form: string;
  42   private _line: string;
  43   private _fallback?: T;
  44
  45   constructor(form: string, line: string, description?: string, fallback?: T) {
  46     super(description || `Reference F${form}.L${line}`);
  47     this._form = form;
  48     this._line = line;
  49     this._fallback = fallback;
  50   }
  51
  52   value(tr: TaxReturn): T {
  53     if (this._fallback !== undefined && !tr.maybeGetForm(this._form))
  54       return this._fallback;
  55     return tr.getForm(this._form).getLine(this._line).value(tr);
  56   }
  57 };
  58
  59 export class InputLine<U = unknown, T extends keyof U = any> extends Line<U[T]> {
  60   private _input: T;
  61
  62   form: Form<any, U>;
  63
  64   constructor(input: T, description?: string) {
  65     super(description || `Input from ${input}`);
  66     this._input = input;
  67   }
  68
  69   value(tr: TaxReturn): U[T] {
  70     return this.form.getInput<T>(this._input);
  71   }
  72 };
  73
  74 export class AccumulatorLine extends Line<number> {
  75   private _form: string;
  76   private _line: string;
  77
  78   constructor(form: string, line: string, description?: string) {
  79     super(description || `Accumulator F${form}.L${line}`);
  80     this._form = form;
  81     this._line = line;
  82   }
  83
  84   value(tr: TaxReturn): number {
  85     const forms = tr.getForms(this._form);
  86     const reducer = (acc: number, curr: Form<any>) => acc + (curr.getValue(tr, this._line) as number);
  87     return forms.reduce(reducer, 0);
  88   }
  89 };