| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | */ |
| 7 | |
| 8 | import getNodeForCharacterOffset from './getNodeForCharacterOffset'; |
| 9 | import {TEXT_NODE} from './HTMLNodeType'; |
| 10 | |
| 11 | /** |
| 12 | * @param {DOMElement} outerNode |
| 13 | * @return {?object} |
| 14 | */ |
| 15 | export function getOffsets(outerNode) { |
| 16 | const {ownerDocument} = outerNode; |
| 17 | const win = (ownerDocument && ownerDocument.defaultView) || window; |
| 18 | const selection = win.getSelection && win.getSelection(); |
| 19 | |
| 20 | if (!selection || selection.rangeCount === 0) { |
| 21 | return null; |
| 22 | } |
| 23 | |
| 24 | const {anchorNode, anchorOffset, focusNode, focusOffset} = selection; |
| 25 | |
| 26 | // In Firefox, anchorNode and focusNode can be "anonymous divs", e.g. the |
| 27 | // up/down buttons on an <input type="number">. Anonymous divs do not seem to |
| 28 | // expose properties, triggering a "Permission denied error" if any of its |
| 29 | // properties are accessed. The only seemingly possible way to avoid erroring |
| 30 | // is to access a property that typically works for non-anonymous divs and |
| 31 | // catch any error that may otherwise arise. See |
| 32 | // https://bugzilla.mozilla.org/show_bug.cgi?id=208427 |
| 33 | try { |
| 34 | /* eslint-disable ft-flow/no-unused-expressions */ |
| 35 | anchorNode.nodeType; |
| 36 | focusNode.nodeType; |
| 37 | /* eslint-enable ft-flow/no-unused-expressions */ |
| 38 | } catch (e) { |
| 39 | return null; |
| 40 | } |
| 41 | |
| 42 | return getModernOffsetsFromPoints( |
| 43 | outerNode, |
| 44 | anchorNode, |
| 45 | anchorOffset, |
| 46 | focusNode, |
| 47 | focusOffset, |
| 48 | ); |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * Returns {start, end} where `start` is the character/codepoint index of |
| 53 | * (anchorNode, anchorOffset) within the textContent of `outerNode`, and |
| 54 | * `end` is the index of (focusNode, focusOffset). |
| 55 | * |
| 56 | * Returns null if you pass in garbage input but we should probably just crash. |
| 57 | * |
| 58 | * Exported only for testing. |
| 59 | */ |
| 60 | export function getModernOffsetsFromPoints( |
| 61 | outerNode, |
| 62 | anchorNode, |
| 63 | anchorOffset, |
| 64 | focusNode, |
| 65 | focusOffset, |
| 66 | ) { |
| 67 | let length = 0; |
| 68 | let start = -1; |
| 69 | let end = -1; |
| 70 | let indexWithinAnchor = 0; |
| 71 | let indexWithinFocus = 0; |
| 72 | let node = outerNode; |
| 73 | let parentNode = null; |
| 74 | |
| 75 | outer: while (true) { |
| 76 | let next = null; |
| 77 | |
| 78 | while (true) { |
| 79 | if ( |
| 80 | node === anchorNode && |
| 81 | (anchorOffset === 0 || node.nodeType === TEXT_NODE) |
| 82 | ) { |
| 83 | start = length + anchorOffset; |
| 84 | } |
| 85 | if ( |
| 86 | node === focusNode && |
| 87 | (focusOffset === 0 || node.nodeType === TEXT_NODE) |
| 88 | ) { |
| 89 | end = length + focusOffset; |
| 90 | } |
| 91 | |
| 92 | if (node.nodeType === TEXT_NODE) { |
| 93 | length += node.nodeValue.length; |
| 94 | } |
| 95 | |
| 96 | if ((next = node.firstChild) === null) { |
| 97 | break; |
| 98 | } |
| 99 | // Moving from `node` to its first child `next`. |
| 100 | parentNode = node; |
| 101 | node = next; |
| 102 | } |
| 103 | |
| 104 | while (true) { |
| 105 | if (node === outerNode) { |
| 106 | // If `outerNode` has children, this is always the second time visiting |
| 107 | // it. If it has no children, this is still the first loop, and the only |
| 108 | // valid selection is anchorNode and focusNode both equal to this node |
| 109 | // and both offsets 0, in which case we will have handled above. |
| 110 | break outer; |
| 111 | } |
| 112 | if (parentNode === anchorNode && ++indexWithinAnchor === anchorOffset) { |
| 113 | start = length; |
| 114 | } |
| 115 | if (parentNode === focusNode && ++indexWithinFocus === focusOffset) { |
| 116 | end = length; |
| 117 | } |
| 118 | if ((next = node.nextSibling) !== null) { |
| 119 | break; |
| 120 | } |
| 121 | node = parentNode; |
| 122 | parentNode = node.parentNode; |
| 123 | } |
| 124 | |
| 125 | // Moving from `node` to its next sibling `next`. |
| 126 | node = next; |
| 127 | } |
| 128 | |
| 129 | if (start === -1 || end === -1) { |
| 130 | // This should never happen. (Would happen if the anchor/focus nodes aren't |
| 131 | // actually inside the passed-in node.) |
| 132 | return null; |
| 133 | } |
| 134 | |
| 135 | return { |
| 136 | start: start, |
| 137 | end: end, |
| 138 | }; |
| 139 | } |
| 140 | |
| 141 | /** |
| 142 | * In modern non-IE browsers, we can support both forward and backward |
| 143 | * selections. |
| 144 | * |
| 145 | * Note: IE10+ supports the Selection object, but it does not support |
| 146 | * the `extend` method, which means that even in modern IE, it's not possible |
| 147 | * to programmatically create a backward selection. Thus, for all IE |
| 148 | * versions, we use the old IE API to create our selections. |
| 149 | * |
| 150 | * @param {DOMElement|DOMTextNode} node |
| 151 | * @param {object} offsets |
| 152 | */ |
| 153 | export function setOffsets(node, offsets) { |
| 154 | const doc = node.ownerDocument || document; |
| 155 | const win = (doc && doc.defaultView) || window; |
| 156 | |
| 157 | // Edge fails with "Object expected" in some scenarios. |
| 158 | // (For instance: TinyMCE editor used in a list component that supports pasting to add more, |
| 159 | // fails when pasting 100+ items) |
| 160 | if (!win.getSelection) { |
| 161 | return; |
| 162 | } |
| 163 | |
| 164 | const selection = win.getSelection(); |
| 165 | const length = node.textContent.length; |
| 166 | let start = Math.min(offsets.start, length); |
| 167 | let end = offsets.end === undefined ? start : Math.min(offsets.end, length); |
| 168 | |
| 169 | // IE 11 uses modern selection, but doesn't support the extend method. |
| 170 | // Flip backward selections, so we can set with a single range. |
| 171 | if (!selection.extend && start > end) { |
| 172 | const temp = end; |
| 173 | end = start; |
| 174 | start = temp; |
| 175 | } |
| 176 | |
| 177 | const startMarker = getNodeForCharacterOffset(node, start); |
| 178 | const endMarker = getNodeForCharacterOffset(node, end); |
| 179 | |
| 180 | if (startMarker && endMarker) { |
| 181 | if ( |
| 182 | selection.rangeCount === 1 && |
| 183 | selection.anchorNode === startMarker.node && |
| 184 | selection.anchorOffset === startMarker.offset && |
| 185 | selection.focusNode === endMarker.node && |
| 186 | selection.focusOffset === endMarker.offset |
| 187 | ) { |
| 188 | return; |
| 189 | } |
| 190 | const range = doc.createRange(); |
| 191 | range.setStart(startMarker.node, startMarker.offset); |
| 192 | selection.removeAllRanges(); |
| 193 | |
| 194 | if (start > end) { |
| 195 | selection.addRange(range); |
| 196 | selection.extend(endMarker.node, endMarker.offset); |
| 197 | } else { |
| 198 | range.setEnd(endMarker.node, endMarker.offset); |
| 199 | selection.addRange(range); |
| 200 | } |
| 201 | } |
| 202 | } |