{"version":3,"file":"skip-link.bundle.mjs","sources":["../../../../src/govuk/common/index.mjs","../../../../src/govuk/errors/index.mjs","../../../../src/govuk/component.mjs","../../../../src/govuk/components/skip-link/skip-link.mjs"],"sourcesContent":["/**\n * Common helpers which do not require polyfill.\n *\n * IMPORTANT: If a helper require a polyfill, please isolate it in its own module\n * so that the polyfill can be properly tree-shaken and does not burden\n * the components that do not need that helper\n */\n\n/**\n * Get GOV.UK Frontend breakpoint value from CSS custom property\n *\n * @private\n * @param {string} name - Breakpoint name\n * @returns {{ property: string, value?: string }} Breakpoint object\n */\nexport function getBreakpoint(name) {\n const property = `--govuk-breakpoint-${name}`\n\n // Get value from `` with breakpoints on CSS :root\n const value = window\n .getComputedStyle(document.documentElement)\n .getPropertyValue(property)\n\n return {\n property,\n value: value || undefined\n }\n}\n\n/**\n * Move focus to element\n *\n * Sets tabindex to -1 to make the element programmatically focusable,\n * but removes it on blur as the element doesn't need to be focused again.\n *\n * @private\n * @template {HTMLElement} FocusElement\n * @param {FocusElement} $element - HTML element\n * @param {object} [options] - Handler options\n * @param {function(this: FocusElement): void} [options.onBeforeFocus] - Callback before focus\n * @param {function(this: FocusElement): void} [options.onBlur] - Callback on blur\n */\nexport function setFocus($element, options = {}) {\n const isFocusable = $element.getAttribute('tabindex')\n\n if (!isFocusable) {\n $element.setAttribute('tabindex', '-1')\n }\n\n /**\n * Handle element focus\n */\n function onFocus() {\n $element.addEventListener('blur', onBlur, { once: true })\n }\n\n /**\n * Handle element blur\n */\n function onBlur() {\n options.onBlur?.call($element)\n\n if (!isFocusable) {\n $element.removeAttribute('tabindex')\n }\n }\n\n // Add listener to reset element on blur, after focus\n $element.addEventListener('focus', onFocus, { once: true })\n\n // Focus element\n options.onBeforeFocus?.call($element)\n $element.focus()\n}\n\n/**\n * Checks if component is already initialised\n *\n * @internal\n * @param {Element} $root - HTML element to be checked\n * @param {string} moduleName - name of component module\n * @returns {boolean} Whether component is already initialised\n */\nexport function isInitialised($root, moduleName) {\n return (\n $root instanceof HTMLElement &&\n $root.hasAttribute(`data-${moduleName}-init`)\n )\n}\n\n/**\n * Checks if GOV.UK Frontend is supported on this page\n *\n * Some browsers will load and run our JavaScript but GOV.UK Frontend\n * won't be supported.\n *\n * @param {HTMLElement | null} [$scope] - (internal) `` HTML element checked for browser support\n * @returns {boolean} Whether GOV.UK Frontend is supported on this page\n */\nexport function isSupported($scope = document.body) {\n if (!$scope) {\n return false\n }\n\n return $scope.classList.contains('govuk-frontend-supported')\n}\n\n/**\n * Check for an array\n *\n * @internal\n * @param {unknown} option - Option to check\n * @returns {boolean} Whether the option is an array\n */\nfunction isArray(option) {\n return Array.isArray(option)\n}\n\n/**\n * Check for an object\n *\n * @internal\n * @template {Partial>} ObjectType\n * @param {unknown | ObjectType} option - Option to check\n * @returns {option is ObjectType} Whether the option is an object\n */\nexport function isObject(option) {\n return !!option && typeof option === 'object' && !isArray(option)\n}\n\n/**\n * Check for valid scope\n *\n * @internal\n * @template {Element | Document} ScopeType\n * @param {unknown | ScopeType} $scope - Scope of the document to search within\n * @returns {$scope is ScopeType} Whether the scope can be queried\n */\nexport function isScope($scope) {\n return !!$scope && ($scope instanceof Element || $scope instanceof Document)\n}\n\n/**\n * Format error message\n *\n * @internal\n * @param {ComponentWithModuleName} Component - Component that threw the error\n * @param {string} message - Error message\n * @returns {string} - Formatted error message\n */\nexport function formatErrorMessage(Component, message) {\n return `${Component.moduleName}: ${message}`\n}\n\n/* eslint-disable jsdoc/valid-types --\n * `{new(...args: any[] ): object}` is not recognised as valid\n * https://github.com/gajus/eslint-plugin-jsdoc/issues/145#issuecomment-1308722878\n * https://github.com/jsdoc-type-pratt-parser/jsdoc-type-pratt-parser/issues/131\n **/\n\n/**\n * @typedef ComponentWithModuleName\n * @property {string} moduleName - Name of the component\n */\n\n/* eslint-enable jsdoc/valid-types */\n","import { formatErrorMessage, isObject } from '../common/index.mjs'\n\n/**\n * GOV.UK Frontend error\n *\n * A base class for `Error`s thrown by GOV.UK Frontend.\n *\n * It is meant to be extended into specific types of errors\n * to be thrown by our code.\n *\n * @example\n * ```js\n * class MissingRootError extends GOVUKFrontendError {\n * // Setting an explicit name is important as extending the class will not\n * // set a new `name` on the subclass. The `name` property is important\n * // to ensure intelligible error names even if the class name gets\n * // mangled by a minifier\n * name = \"MissingRootError\"\n * }\n * ```\n * @virtual\n */\nexport class GOVUKFrontendError extends Error {\n name = 'GOVUKFrontendError'\n}\n\n/**\n * Indicates that GOV.UK Frontend is not supported\n */\nexport class SupportError extends GOVUKFrontendError {\n name = 'SupportError'\n\n /**\n * Checks if GOV.UK Frontend is supported on this page\n *\n * @param {HTMLElement | null} [$scope] - HTML element `` checked for browser support\n */\n constructor($scope = document.body) {\n const supportMessage =\n 'noModule' in HTMLScriptElement.prototype\n ? 'GOV.UK Frontend initialised without `` from template `