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January 28, 2017 06:57
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Gets line number of an HTML element.
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| /** | |
| * Gets the line number of an element in an HTML element | |
| * @return number -1 if not found | |
| * @example | |
| * getLineNo(document.body) | |
| * @caveat | |
| * This function assumes that <html>, </html>, and the DOCTYPE | |
| * declaration are all on their own lines. If this isn't the case, | |
| * you can adjust options.numLinesForHTMLElement. ALSO, I didn't | |
| * make any concessions for browser support, but the general technique | |
| * should across browsers. ALSO, this technique is totally useless if | |
| * you want the ORIGINAL source line number and some other JS already | |
| * messed with the DOM where the element lives | |
| */ | |
| function getLineNo(element, options = {}) { | |
| for (const key in getLineNo.defaultOptions) { | |
| if (!(key in options)) options[key] = getLineNo.defaultOptions[key] | |
| } | |
| const MAX_I = 100 | |
| let prev | |
| let i = 0 | |
| let curr = element | |
| // Get the root node for this element | |
| while (curr.parentElement !== null && ++i < options.maxIterationsForRoot) { | |
| curr = curr.parentElement | |
| } | |
| if (i === MAX_I) return -1 | |
| // Apply a unique identifier to the element that's very unlikely to | |
| // have gotten here otherwise | |
| const id = getLineNo.uuid() | |
| const searchFor = `data-search-id="${id}"` | |
| element.dataset.searchId = id | |
| const lines = curr.innerHTML.split('\n') | |
| // Find the line containing our id | |
| for (let i = 0; i < lines.length; i++) { | |
| if (lines[i].indexOf(searchFor) > -1) { | |
| delete element.dataset.searchId | |
| return i + options.numLinesForHTMLElement | |
| } | |
| } | |
| delete element.dataset.searchId | |
| return -1 | |
| } | |
| getLineNo.defaultOptions = { | |
| // This includes html open, close, and the doctype | |
| numLinesForHTMLElement: 3, | |
| // Maximum amount of times we check for parent before breaking | |
| // the loop to avoid possible infinite loops | |
| maxIterationsForRoot: 100, | |
| } | |
| // Credit: http://stackoverflow.com/a/2117523 | |
| getLineNo.uuid = function uuid(){ | |
| return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) { | |
| var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8) | |
| return v.toString(16) | |
| }) | |
| } |
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