@barchart/common-js/specifications/compound/Within.js

Library of common JavaScript utilities

const is = require('./../../lang/is');

const Specification = require('./../Specification');

module.exports = (() => {
	'use strict';

	/**
	 * A {@link Specification} that passes when the absolute difference between the
	 * first item and second items in an array is less than or equal to a tolerance
	 * value.
	 *
	 * @public
	 * @extends {Specification}
	 * @param {Number} tolerance
	 */
	class Within extends Specification {
		constructor(tolerance) {
			super();

			this._tolerance = tolerance;
		}

		_evaluate(data) {
			return is.array(data) && data.length === 2 && Math.abs(data[0] - data[1]) <= this._tolerance;
		}

		toString() {
			return '[Within]';
		}
	}

	return Within;
})();