number-property.ts

/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.dev/license
 */

/**
 * Type describing the allowed values for a number input
 * @docs-private
 */
export type NumberInput = string | number | null | undefined;

/** Coerces a data-bound value (typically a string) to a number. */
export function coerceNumberProperty(value: unknown): number;
export function coerceNumberProperty<D>(value: unknown, fallback: D): number | D;
export function coerceNumberProperty(value: unknown, fallbackValue = 0) {
  if (_isNumberValue(value)) {
    return Number(value);
  }
  return arguments.length === 2 ? fallbackValue : 0;
}

/**
 * Whether the provided value is considered a number.
 * @docs-private
 */
export function _isNumberValue(value: unknown): boolean {
  // parseFloat(value) handles most of the cases we're interested in (it treats null, empty string,
  // and other non-number values as NaN, where Number just uses 0) but it considers the string
  // '123hello' to be a valid number. Therefore we also check if Number(value) is NaN.
  return !isNaN(parseFloat(String(value))) && !isNaN(Number(value));
}