MDL-68390 aria: Add new core_aria module
[moodle.git] / lib / amd / build / local / aria / focuslock.min.js.map
CommitLineData
04e67878 1{"version":3,"sources":["../../../src/local/aria/focuslock.js"],"names":["selectors","focusable","lockRegionStack","initialFocusElementStack","finalFocusElementStack","lastFocus","ignoreFocusChanges","isLocked","lockHandler","event","lockRegion","getCurrentLockRegion","parentNode","untrapFocus","contains","target","focusFirstDescendant","document","activeElement","focusLastDescendant","focusableElements","Array","from","querySelectorAll","unshift","some","focusableElement","attemptFocus","reverse","push","isFocusable","focusTarget","tabIndex","getAttribute","disabled","nodeName","href","rel","type","focus","e","length","addLockRegionToStack","newLockRegion","currentLockRegion","element","createElement","style","position","top","left","initialNode","cloneNode","insertBefore","finalNode","nextSibling","removeLastLockRegionFromStack","pop","remove","hasTrappedRegionsInStack","trapFocus","addEventListener","originalRegionTabIndex","removeEventListener"],"mappings":"8JA2BMA,CAAAA,CAAS,CAAG,CACdC,SAAS,CAAE,6EADG,C,CAIZC,CAAe,CAAG,E,CAClBC,CAAwB,CAAG,E,CAC3BC,CAAsB,CAAG,E,CAE3BC,CAAS,CAAG,I,CACZC,CAAkB,G,CAClBC,CAAQ,G,CAiBNC,CAAW,CAAG,SAAAC,CAAK,CAAI,CACzB,GAAIH,CAAJ,CAAwB,CAEpB,MACH,CAED,GAAMI,CAAAA,CAAU,CAAGC,CAAoB,EAAvC,CAEA,GAAI,CAACD,CAAU,CAACE,UAAhB,CAA4B,CAGxBC,CAAW,EACd,CAED,GAAIH,CAAU,CAACI,QAAX,CAAoBL,CAAK,CAACM,MAA1B,CAAJ,CAAuC,CACnCV,CAAS,CAAGI,CAAK,CAACM,MACrB,CAFD,IAEO,CACHC,CAAoB,GACpB,GAAIX,CAAS,EAAIY,QAAQ,CAACC,aAA1B,CAAyC,CACrCC,CAAmB,EACtB,CACDd,CAAS,CAAGY,QAAQ,CAACC,aACxB,CACJ,C,CAOKF,CAAoB,CAAG,UAAM,IACzBN,CAAAA,CAAU,CAAGC,CAAoB,EADR,CAQzBS,CAAiB,CAAGC,KAAK,CAACC,IAAN,CAAWZ,CAAU,CAACa,gBAAX,CAA4BvB,CAAS,CAACC,SAAtC,CAAX,CARK,CAY/BmB,CAAiB,CAACI,OAAlB,CAA0Bd,CAA1B,EACA,MAAOU,CAAAA,CAAiB,CAACK,IAAlB,CAAuB,SAAAC,CAAgB,QAAIC,CAAAA,CAAY,CAACD,CAAD,CAAhB,CAAvC,CACV,C,CAOKP,CAAmB,CAAG,UAAM,IACxBT,CAAAA,CAAU,CAAGC,CAAoB,EADT,CAQxBS,CAAiB,CAAGC,KAAK,CAACC,IAAN,CAAWZ,CAAU,CAACa,gBAAX,CAA4BvB,CAAS,CAACC,SAAtC,CAAX,EAA6D2B,OAA7D,EARI,CAY9BR,CAAiB,CAACS,IAAlB,CAAuBnB,CAAvB,EACA,MAAOU,CAAAA,CAAiB,CAACK,IAAlB,CAAuB,SAAAC,CAAgB,QAAIC,CAAAA,CAAY,CAACD,CAAD,CAAhB,CAAvC,CACV,C,CAWKI,CAAW,CAAG,SAAAC,CAAW,CAAI,CAC/B,GAA2B,CAAvB,CAAAA,CAAW,CAACC,QAAZ,EAAsD,CAAzB,GAAAD,CAAW,CAACC,QAAZ,EAAuE,IAAzC,GAAAD,CAAW,CAACE,YAAZ,CAAyB,UAAzB,CAA/D,CAA+G,CAC3G,QACH,CAED,GAAIF,CAAW,CAACG,QAAhB,CAA0B,CACtB,QACH,CAED,OAAQH,CAAW,CAACI,QAApB,EACI,IAAK,GAAL,CACI,MAAO,CAAC,CAACJ,CAAW,CAACK,IAAd,EAAyC,QAAnB,EAAAL,CAAW,CAACM,GAAzC,CACJ,IAAK,OAAL,CACI,MAA2B,QAApB,EAAAN,CAAW,CAACO,IAAZ,EAAoD,MAApB,EAAAP,CAAW,CAACO,IAAnD,CACJ,IAAK,QAAL,CACA,IAAK,QAAL,CACA,IAAK,UAAL,CACI,SACJ,QACI,SAVR,CAYH,C,CAUKX,CAAY,CAAG,SAAAI,CAAW,CAAI,CAChC,GAAI,CAACD,CAAW,CAACC,CAAD,CAAhB,CAA+B,CAC3B,QACH,CAGDzB,CAAkB,GAAlB,CAEA,GAAI,CACAyB,CAAW,CAACQ,KAAZ,EACH,CAAC,MAAOC,CAAP,CAAU,CAGX,CAEDlC,CAAkB,GAAlB,CAGA,MAAQW,CAAAA,QAAQ,CAACC,aAAT,GAA2Ba,CACtC,C,CAOKpB,CAAoB,CAAG,UAAM,CAC/B,MAAOT,CAAAA,CAAe,CAACA,CAAe,CAACuC,MAAhB,CAAyB,CAA1B,CACzB,C,CAOKC,CAAoB,CAAG,SAAAC,CAAa,CAAI,CAC1C,GAAIA,CAAa,GAAKhC,CAAoB,EAA1C,CAA8C,CAC1C,MACH,CAEDT,CAAe,CAAC2B,IAAhB,CAAqBc,CAArB,EAL0C,GAMpCC,CAAAA,CAAiB,CAAGjC,CAAoB,EANJ,CAYpCkC,CAAO,CAAG5B,QAAQ,CAAC6B,aAAT,CAAuB,KAAvB,CAZ0B,CAa1CD,CAAO,CAACb,QAAR,CAAmB,CAAnB,CACAa,CAAO,CAACE,KAAR,CAAcC,QAAd,CAAyB,OAAzB,CACAH,CAAO,CAACE,KAAR,CAAcE,GAAd,CAAoB,CAApB,CACAJ,CAAO,CAACE,KAAR,CAAcG,IAAd,CAAqB,CAArB,CAEA,GAAMC,CAAAA,CAAW,CAAGN,CAAO,CAACO,SAAR,EAApB,CACAR,CAAiB,CAAChC,UAAlB,CAA6ByC,YAA7B,CAA0CF,CAA1C,CAAuDP,CAAvD,EACAzC,CAAwB,CAAC0B,IAAzB,CAA8BsB,CAA9B,EAEA,GAAMG,CAAAA,CAAS,CAAGT,CAAO,CAACO,SAAR,EAAlB,CACAR,CAAiB,CAAChC,UAAlB,CAA6ByC,YAA7B,CAA0CC,CAA1C,CAAqDV,CAAiB,CAACW,WAAvE,EACAnD,CAAsB,CAACyB,IAAvB,CAA4ByB,CAA5B,CACH,C,CAKKE,CAA6B,CAAG,UAAM,CAExCtD,CAAe,CAACuD,GAAhB,GAEA,GAAMH,CAAAA,CAAS,CAAGlD,CAAsB,CAACqD,GAAvB,EAAlB,CACA,GAAIH,CAAJ,CAAe,CAEXA,CAAS,CAACI,MAAV,EACH,CAED,GAAMP,CAAAA,CAAW,CAAGhD,CAAwB,CAACsD,GAAzB,EAApB,CACA,GAAIN,CAAJ,CAAiB,CAEbA,CAAW,CAACO,MAAZ,EACH,CACJ,C,CAOKC,CAAwB,CAAG,UAAM,CACnC,MAAO,CAAC,CAACzD,CAAe,CAACuC,MAC5B,C,CAOYmB,CAAS,CAAG,SAAAjB,CAAa,CAAI,CAGtCD,CAAoB,CAACC,CAAD,CAApB,CAEA,GAAI,CAACpC,CAAL,CAAe,CAEXU,QAAQ,CAAC4C,gBAAT,CAA0B,OAA1B,CAAmCrD,CAAnC,IACH,CAGD,GAAI,CAACQ,CAAoB,EAAzB,CAA6B,IACnB4B,CAAAA,CAAiB,CAAGjC,CAAoB,EADrB,CAMnBmD,CAAsB,CAAGlB,CAAiB,CAACZ,QANxB,CAOzBY,CAAiB,CAACZ,QAAlB,CAA6B,CAA7B,CACAL,CAAY,CAACiB,CAAD,CAAZ,CACAA,CAAiB,CAACZ,QAAlB,CAA6B8B,CAChC,CAGDzD,CAAS,CAAGY,QAAQ,CAACC,aAArB,CAEAX,CAAQ,GACX,C,eAKM,GAAMM,CAAAA,CAAW,CAAG,UAAM,CAE7B2C,CAA6B,GAE7B,GAAIG,CAAwB,EAA5B,CAAgC,CAE5B,MACH,CAED1C,QAAQ,CAAC8C,mBAAT,CAA6B,OAA7B,CAAsCvD,CAAtC,KAEAH,CAAS,CAAG,IAAZ,CACAC,CAAkB,GAAlB,CACAC,CAAQ,GACX,CAdM,C","sourcesContent":["// This file is part of Moodle - http://moodle.org/\n//\n// Moodle is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n//\n// Moodle is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\n// GNU General Public License for more details.\n//\n// You should have received a copy of the GNU General Public License\n// along with Moodle. If not, see <http://www.gnu.org/licenses/>.\n\n/**\n * Tab locking system.\n *\n * This is based on code and examples provided in the ARIA specification.\n * https://www.w3.org/TR/wai-aria-practices/examples/dialog-modal/dialog.html\n *\n * @module core/tablock\n * @class tablock\n * @package core\n * @copyright 2019 Andrew Nicols <andrew@nicols.co.uk>\n * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later\n */\nconst selectors = {\n focusable: 'input:not([type=\"hidden\"]), a[href], button, textarea, select, [tabindex]',\n};\n\nconst lockRegionStack = [];\nconst initialFocusElementStack = [];\nconst finalFocusElementStack = [];\n\nlet lastFocus = null;\nlet ignoreFocusChanges = false;\nlet isLocked = false;\n\n/**\n * The lock handler.\n *\n * This is the item that does a majority of the work.\n * The overall logic from this comes from the examles in the WCAG guidelines.\n *\n * The general idea is that if the focus is not held within by an Element within the lock region, then we replace focus\n * on the first element in the lock region. If the first element is the element previously selected prior to the\n * user-initiated focus change, then instead jump to the last element in the lock region.\n *\n * This gives us a solution which supports focus locking of any kind, which loops in both directions, and which\n * prevents the lock from escaping the modal entirely.\n *\n * @param {Event} event The event from the focus change\n */\nconst lockHandler = event => {\n if (ignoreFocusChanges) {\n // The focus change was made by an internal call to set focus.\n return;\n }\n\n const lockRegion = getCurrentLockRegion();\n\n if (!lockRegion.parentNode) {\n // The lock region does not exist.\n // Perhaps it was removed without being untrapped.\n untrapFocus();\n }\n\n if (lockRegion.contains(event.target)) {\n lastFocus = event.target;\n } else {\n focusFirstDescendant();\n if (lastFocus == document.activeElement) {\n focusLastDescendant();\n }\n lastFocus = document.activeElement;\n }\n};\n\n/**\n * Focus the first descendant of the current lock region.\n *\n * @returns {Bool} Whether a node was focused\n */\nconst focusFirstDescendant = () => {\n const lockRegion = getCurrentLockRegion();\n\n // Grab all elements in the lock region and attempt to focus each element until one is focused.\n // We can capture most of this in the query selector, but some cases may still reject focus.\n // For example, a disabled text area cannot be focused, and it becomes difficult to provide a decent query selector\n // to capture this.\n // The use of Array.some just ensures that we stop as soon as we have a successful focus.\n const focusableElements = Array.from(lockRegion.querySelectorAll(selectors.focusable));\n\n // The lock region itself may be focusable. This is particularly true on Moodle's older dialogues.\n // We must include it in the calculation of descendants to ensure that looping works correctly.\n focusableElements.unshift(lockRegion);\n return focusableElements.some(focusableElement => attemptFocus(focusableElement));\n};\n\n/**\n * Focus the last descendant of the current lock region.\n *\n * @returns {Bool} Whether a node was focused\n */\nconst focusLastDescendant = () => {\n const lockRegion = getCurrentLockRegion();\n\n // Grab all elements in the lock region, reverse them, and attempt to focus each element until one is focused.\n // We can capture most of this in the query selector, but some cases may still reject focus.\n // For example, a disabled text area cannot be focused, and it becomes difficult to provide a decent query selector\n // to capture this.\n // The use of Array.some just ensures that we stop as soon as we have a successful focus.\n const focusableElements = Array.from(lockRegion.querySelectorAll(selectors.focusable)).reverse();\n\n // The lock region itself may be focusable. This is particularly true on Moodle's older dialogues.\n // We must include it in the calculation of descendants to ensure that looping works correctly.\n focusableElements.push(lockRegion);\n return focusableElements.some(focusableElement => attemptFocus(focusableElement));\n};\n\n/**\n * Check whether the supplied focusTarget is actually focusable.\n * There are cases where a normally focusable element can reject focus.\n *\n * Note: This example is a wholesale copy of the WCAG example.\n *\n * @param {HTMLElement} focusTarget\n * @returns {Bool}\n */\nconst isFocusable = focusTarget => {\n if (focusTarget.tabIndex > 0 || (focusTarget.tabIndex === 0 && focusTarget.getAttribute('tabIndex') !== null)) {\n return true;\n }\n\n if (focusTarget.disabled) {\n return false;\n }\n\n switch (focusTarget.nodeName) {\n case 'A':\n return !!focusTarget.href && focusTarget.rel != 'ignore';\n case 'INPUT':\n return focusTarget.type != 'hidden' && focusTarget.type != 'file';\n case 'BUTTON':\n case 'SELECT':\n case 'TEXTAREA':\n return true;\n default:\n return false;\n }\n};\n\n/**\n * Attempt to focus the supplied focusTarget.\n *\n * Note: This example is a heavily inspired by the WCAG example.\n *\n * @param {HTMLElement} focusTarget\n * @returns {Bool} Whether focus was successful o rnot.\n */\nconst attemptFocus = focusTarget => {\n if (!isFocusable(focusTarget)) {\n return false;\n }\n\n // The ignoreFocusChanges variable prevents the focus event handler from interfering and entering a fight with itself.\n ignoreFocusChanges = true;\n\n try {\n focusTarget.focus();\n } catch (e) {\n // Ignore failures. We will just try to focus the next element in the list.\n // eslint-disable-line\n }\n\n ignoreFocusChanges = false;\n\n // If focus was successful the activeElement will be the one we focused.\n return (document.activeElement === focusTarget);\n};\n\n/**\n * Get the current lock region from the top of the stack.\n *\n * @returns {HTMLElement}\n */\nconst getCurrentLockRegion = () => {\n return lockRegionStack[lockRegionStack.length - 1];\n};\n\n/**\n * Add a new lock region to the stack.\n *\n * @param {HTMLElement} newLockRegion\n */\nconst addLockRegionToStack = newLockRegion => {\n if (newLockRegion === getCurrentLockRegion()) {\n return;\n }\n\n lockRegionStack.push(newLockRegion);\n const currentLockRegion = getCurrentLockRegion();\n\n // Append an empty div which can be focused just outside of the item locked.\n // This locks tab focus to within the tab region, and does not allow it to extend back into the window by\n // guaranteeing the existence of a tabable item after the lock region which can be focused but which will be caught\n // by the handler.\n const element = document.createElement('div');\n element.tabIndex = 0;\n element.style.position = 'fixed';\n element.style.top = 0;\n element.style.left = 0;\n\n const initialNode = element.cloneNode();\n currentLockRegion.parentNode.insertBefore(initialNode, currentLockRegion);\n initialFocusElementStack.push(initialNode);\n\n const finalNode = element.cloneNode();\n currentLockRegion.parentNode.insertBefore(finalNode, currentLockRegion.nextSibling);\n finalFocusElementStack.push(finalNode);\n};\n\n/**\n * Remove the top lock region from the stack.\n */\nconst removeLastLockRegionFromStack = () => {\n // Take the top element off the stack, and replce the current lockRegion value.\n lockRegionStack.pop();\n\n const finalNode = finalFocusElementStack.pop();\n if (finalNode) {\n // The final focus element may have been removed if it was part of a parent item.\n finalNode.remove();\n }\n\n const initialNode = initialFocusElementStack.pop();\n if (initialNode) {\n // The initial focus element may have been removed if it was part of a parent item.\n initialNode.remove();\n }\n};\n\n/**\n * Whether any region is left in the stack.\n *\n * @return {Bool}\n */\nconst hasTrappedRegionsInStack = () => {\n return !!lockRegionStack.length;\n};\n\n/**\n * Start trapping the focus and lock it to the specified newLockRegion.\n *\n * @param {HTMLElement} newLockRegion The container to lock focus to\n */\nexport const trapFocus = newLockRegion => {\n // Update the lock region stack.\n // This allows us to support nesting.\n addLockRegionToStack(newLockRegion);\n\n if (!isLocked) {\n // Add the focus handler.\n document.addEventListener('focus', lockHandler, true);\n }\n\n // Attempt to focus on the first item in the lock region.\n if (!focusFirstDescendant()) {\n const currentLockRegion = getCurrentLockRegion();\n\n // No focusable descendants found in the region yet.\n // This can happen when the region is locked before content is generated.\n // Focus on the region itself for now.\n const originalRegionTabIndex = currentLockRegion.tabIndex;\n currentLockRegion.tabIndex = 0;\n attemptFocus(currentLockRegion);\n currentLockRegion.tabIndex = originalRegionTabIndex;\n }\n\n // Keep track of the last item focused.\n lastFocus = document.activeElement;\n\n isLocked = true;\n};\n\n/**\n * Stop trapping the focus.\n */\nexport const untrapFocus = () => {\n // Remove the top region from the stack.\n removeLastLockRegionFromStack();\n\n if (hasTrappedRegionsInStack()) {\n // The focus manager still has items in the stack.\n return;\n }\n\n document.removeEventListener('focus', lockHandler, true);\n\n lastFocus = null;\n ignoreFocusChanges = false;\n isLocked = false;\n};\n"],"file":"focuslock.min.js"}