riot/esm/dependencies/@riotjs/util/checks.js

Simple and elegant component-based UI library

/* Riot WIP, @license MIT */
import { EVENT_ATTRIBUTE_RE } from './constants.js';

/**
 * Quick type checking
 * @param   {*} element - anything
 * @param   {string} type - type definition
 * @returns {boolean} true if the type corresponds
 */
function checkType(element, type) {
  return typeof element === type
}

/**
 * Check if an element is part of an svg
 * @param   {HTMLElement}  el - element to check
 * @returns {boolean} true if we are in an svg context
 */
function isSvg(el) {
  const owner = el.ownerSVGElement;

  return !!owner || owner === null
}

/**
 * Check if an element is a template tag
 * @param   {HTMLElement}  el - element to check
 * @returns {boolean} true if it's a <template>
 */
function isTemplate(el) {
  return el.tagName.toLowerCase() === 'template'
}

/**
 * Check that will be passed if its argument is a function
 * @param   {*} value - value to check
 * @returns {boolean} - true if the value is a function
 */
function isFunction(value) {
  return checkType(value, 'function')
}

/**
 * Check if a value is a Boolean
 * @param   {*}  value - anything
 * @returns {boolean} true only for the value is a boolean
 */
function isBoolean(value) {
  return checkType(value, 'boolean')
}

/**
 * Check if a value is an Object
 * @param   {*}  value - anything
 * @returns {boolean} true only for the value is an object
 */
function isObject(value) {
  return !isNil(value) && value.constructor === Object
}

/**
 * Check if a value is null or undefined
 * @param   {*}  value - anything
 * @returns {boolean} true only for the 'undefined' and 'null' types
 */
function isNil(value) {
  return value === null || value === undefined
}

/**
 * Detect node js environment
 * @returns {boolean} true if the runtime is node
 */
function isNode() {
  return typeof globalThis.process !== 'undefined'
}

/**
 * Check if an attribute is a DOM handler
 * @param   {string} attribute - attribute string
 * @returns {boolean} true only for dom listener attribute nodes
 */
function isEventAttribute(attribute) {
  return EVENT_ATTRIBUTE_RE.test(attribute)
}

export { checkType, isBoolean, isEventAttribute, isFunction, isNil, isNode, isObject, isSvg, isTemplate };