evaluate-value

Return a value or an evaluated function (with arguments).

• When the first input argument is a function, it is executed with the remaining arguments, and the result is returned.
• When the first input argument is not a function, it is simply returned.

Install

npm install evaluate-value

Usage

import evaluateValue from 'evaluate-value';

evaluateValue(true); //-> true

evaluateValue(() => true); //-> true

evaluateValue((arg1, arg2) => arg1 + arg2, 2, 2); //-> 4

An EvaluateValueArgs type is exposed for convenient wrapping:

import { type EvaluateValueArgs } from 'evaluate-value';

interface Options {
  prop: (arg: string) => boolean;
}

const DEFAULT_OPTIONS: Options = {
  prop: arg => arg === 'something',
};

/**
 * Fallback to the default value for a specific option if there's no custom value.
 */
const defaultFallback = <K extends keyof typeof DEFAULT_OPTIONS>(
  options: Options | undefined,
  name: K,
  ...args: EvaluateValueArgs<Options[K]>
) => evaluateValue(options?.[name], ...args) ?? evaluateValue(DEFAULT_OPTIONS[name], ...args);